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Is the Current Bivalent Booster the Correct One? Studies Suggest it Isn’t

Kevin Kavanagh wrote . . . . . . . . .

The United States may be on the precipice of a rude awakening regarding the persistence and devastation of COVID-19. A perfect storm is brewing with the convergence of 3 untoward outcomes: The bivalent booster may primarily elicit imprinted immunity, a deadly brew of a plethora of immune escape variants is forming, and our public has thrown safety to the wind with few—if any—masking or bothering to optimize their immunity. All of this is in the background of new and disturbing data regarding the dangers of long COVID-19.

A recently posted study from Columbia and the University of Michigan found that the immune response elicited by the new bivalent booster was similar to the old univalent booster for “all SARS-CoV-2 variants tested, including BA.4/BA.5.” This finding supports my concerns regarding the bivalent booster and the phenomenon of immune imprinting or “antigenic sin.” In other words, the type of immune response you produce is based upon the virus you were first exposed to (whether through vaccination or infection) and future exposures do little to modify the type of response elicited. A second study3 from Harvard also found comparable BA.5 antibody titers with the monovalent ancestral and bivalent boosters.

I first discussed this concern in an Infection Control Today® article regarding data presented before the Centers for Disease Control and Prevention’s (CDC’s) September 2022 Association for Professionals in Infection Control and Epidemiology committee meeting. The safety of the booster has never been in question. What is debated is if it will be any more effective than the booster based upon the ancestral strain. The presented data, which was derived from mice, found that the monovalent BA.5 booster (which is not clinically available) produced a response to the ancestral strain which was similar to that of the ancestral monovalent booster. However, the monovalent BA.5 booster produced a 6-fold increase in antibodies to the BA.5 variant, as the hybrid Ancestral/BA.5 booster (which is clinically available) produced a 2.6-fold increase. With this data, one must wonder why the univalent BA.5 booster was not chosen for clinical use.

But this finding was in mice. The human laboratory data reported by the University of Michigan found that the response elicited by the bivalent booster was similar to the response elicited by the bivalent Ancestral/BA.5 booster for all SARS-CoV-2 variants.

This is not good news. The immune escape potential of the BA.5 variant and not having a refined immune response, places all of us at risk. What is even more concerning is that if our immune response is imprinted to the original virus we are exposed to, what will happen with the new, even more immune evasive variants which are in circulation? Currently, the BQ.1 and BQ.1.1 variants are even more evasive and comprise 27% of all sequenced specimens in the United States. The BA.4.6 and BF.7 are also slowly increasing their proportion in the reported specimens. And the XBB6 and BA.5.2.67 variants are looming; both are circulating in the United States in low percentages. We are faced with a soup of variants8, which because of their high infectivity can search out the most suitable host to infect.

There are concerns that the BQ.1 and BQ.1.1 may not only be more infectious but also more lethal as compared to the BA.1 (original omicron) variant.

Almost solely relying upon a vaccine/booster whose effectiveness appears to be imprinted in the past, to combat a virus which is progressively evading immunity, is unlikely to be an effective plan. We need to enact other strategies, such as masking and curtailing activities in high-risk venues.

To this end, the new CDC commercial entitled ”Just In Time: Updated COVID-19 Vaccines,”10 appears to be counterproductive. The commercial is designed to encourage vaccinations. No one is wearing a mask, even in crowded indoor places. The message I fear that is being transmitted is that if you are vaccinated all will be well and you do not have to take other precautions.

I know of 5 individuals who have recently contracted symptomatic COVID-19 after receiving the bivalent booster. All had truly mild symptoms and did not develop long COVID-19. But the latter is always a concern, and it is the reason why we need to continue vigilance even if boosted, and if one becomes infected to seek medical care to obtain an antiviral therapeutic.

Should the new bivalent booster help? The answer is most assuredly “yes” but it is only 1 layer of armor. We also need to take additional steps. This means continuing to wear masks in high-risk settings and avoiding indoor crowded places. Even with the new bivalent booster, it is unwise to place yourself, without a mask, in a crowded elevator.


Source : Infection Control Today

Will ‘Centaurus’ be the Next Global Coronavirus Variant? Indian Cases Offers Clues

Ewen Callaway wrote . . . . . . . . .

As countries await the end of COVID-19 surges caused by the variant BA.5, researchers are on the lookout for what will come next.

An Omicron subvariant called BA.2.75 — and nicknamed ‘Centaurus’ by some on social media — is rising fast in India. A few scientists are sounding the alarm, whereas others say it’s too early to tell whether the variant will spread widely. In India, it doesn’t yet seem to be driving up hospitalization or death rates.

BA.2.75 has been detected in more than 20 countries worldwide, and researchers are waiting to learn whether it will substantially elevate case numbers after a wave of infections with BA.5.

A slew of studies suggests that the two variants have roughly similar capacities to dodge immunity conferred by infection and vaccination. This suggests that ‘Centaurus’ might not push cases much higher outside India — at least not while population immunity is high and before the variant picks up many extra mutations.

On the alert

Surveillance of SARS-CoV-2 variants is falling by the wayside in many countries, but India seems to be at the epicentre of the spread of BA.2.75. This mutation-laden lineage evolved from the BA.2 subvariant of Omicron, which spread widely in early 2022 (see ‘Pathogen progression’).

Researchers in India have sequenced more than 1,000 samples of the variant since May. The data suggest that about two-thirds of new cases there are currently caused by BA.2.75, says Shahid Jameel, a virologist at the University of Oxford, UK, who previously led India’s SARS-CoV-2 sequencing consortium (see ‘‘Centaurus’ grows’).

The variant seems to have a “quite sizeable” transmission advantage over BA.5 in India, says Tom Wenseleers, an evolutionary biologist at the Catholic University of Leuven in Belgium, who has modelled its rise. “This would definitely cause an infection wave,” he says. The number of confirmed infections — a sliver of the probable true number — is up across India, Wenseleers notes, as is the percentage of tests that come back positive (a more reliable measure when testing rates are low).

So far, BA.2.75 has been detected at relatively low rates outside India, in countries including Japan, the United States and the United Kingdom, which are in the middle of or just past the peaks of surges caused mainly by BA.5.

As a result, Jameel does not expect BA.2.75 to trigger big waves in most places. “We’re coming to a point where these variants are sort of competing with each other and they’re almost equivalent,” he says. “I think people who have had BA.5 will not have a breakthrough infections with BA.2.75, and vice versa.”

Neck and neck

Laboratory studies posted on preprint servers in recent weeks lend credence to this idea1–5. Several teams have found that the two variants have a similar ability to evade antibodies triggered by vaccination and previous infection, with BA.5 showing a slight edge over its distant cousin. This makes BA.2.75’s rise in India — where BA.5 is also present — fairly perplexing, says Yunlong Richard Cao, an immunologist at Peking University in Beijing who co-led one of the studies1. “It’s weird.”

His team thinks that India’s immunity profile is part of the explanation. In 2021, the country saw an explosive wave of cases caused by the Delta variant, which shares a key mutation with BA.5. Cao suspects that previous Delta infections provide added protection against BA.5, leaving an opening for BA.2.75.

Cao and his team found that several people who had had Delta infections after vaccination produced antibodies that were more potent against BA.5 than against BA.2.75. “My guess is that BA.2.75 probably won’t prevail that much outside India”, especially in countries that weren’t hit hard by Delta, Cao adds.

Other researchers say the small number of Delta infections after vaccination in Cao and his colleagues’ study means the hypothesis should be treated with caution. Moreover, Wenseleers has found tentative signs that BA.2.75 might be spreading a little faster than BA.5 in some countries, including Australia, the United Kingdom, the United States and Canada.

He predicts that BA.2.75 will continue to grow globally, particularly in Asia and Oceania. But there are also signs that another Omicron sub-lineage that’s growing in Europe and North America, called BA.4.6, is just as transmissible as BA.2.75. “We might end up with an eclectic mix of Omicron descendants, with different ones reaching dominance in different parts of the world,” Wenseleers says.

No hospitalization surge

So far, India isn’t seeing a significant rise in hospitalizations from its ‘Centaurus’ wave, says Jameel, who gives credit to the combined effects of high rates of vaccination and of previous infection. “This hybrid immunity is going to largely protect and keep people out of hospitals,” he adds.

Wenseleers and others expect the same pattern to be repeated elsewhere — whether the next variant is BA.2.75 or something else entirely. “Higher and higher population immunity leads to less and less severe consequences for most people,” he says.

If BA.2.75 doesn’t spread widely now, it could in several months’ time, as it picks up new immune-evading mutations and protection caused by BA.5 infection wanes, says Cao. Some BA.2.75 sequences include a mutation found in BA.5, called L452R, that could augment the variant’s ability to reinfect people, he adds. “This is what makes it scary.”

Even if hospitalization and death rates stay low in a wave caused by Centaurus or whatever comes next, researchers say, the high frequency of infection waves could mean more long COVID and general disruption caused by high levels of illness. “The next thing we need to do is bring down infection volumes,” says Wenseleers. “At the end of the day, that’s the problem.”


Source : Nature

COVID Virus’ Incubation Time Gets Shorter With Each New Variant

If you get infected with COVID-19, the time from infection to possible onset of symptoms — the incubation period — is significantly shorter now than it was at the beginning of the pandemic, new research shows.

Researchers in China who looked at data from 142 different studies found that people who got infected with the Alpha variant — the one that emerged in Wuhan in late 2019 — had an incubation period averaging five days.

By the time the Omicron variant arrived, incubation had shortened to less than 3.5 days, on average, the investigators reported.

The findings have real-world importance, because “identifying the incubation period of different variants is a key factor in determining the isolation period” for folks testing positive for COVID-19, the research team explained.

The new study was led by Min Liu, of the Department of Epidemiology and Biostatistics at Peking University’s School of Public Health in Beijing.

The researchers examined data on incubation periods from a myriad of studies conducted throughout the pandemic. A total of more than 8,100 COVID-19 patients were included.

“The findings of this study suggest that SARS-CoV-2 has evolved and mutated continuously throughout the COVID-19 pandemic,” Liu’s group said. The virus has constantly changed in terms of its ability to transmit between people, its level of severity, and its incubation period.

Focusing on incubation, the researchers found that the early Alpha variant COVID virus had an average incubation of five days before symptom onset.

When the Beta variant emerged in May 2020, that incubation rate had shortened to about 4.5 days.

The more highly transmissible Delta variant came on the scene in 2021. Its incubation period was even shorter, about 4.4 days, on average.

Incubation time became significantly shorter with the advent of the Omicron variant, however: Just 3.4 days, on average, according to the Chinese team.

They noted that when COVID-19 first emerged in its Alpha variant, its five-day incubation period was much longer than that seen with other common viral illnesses.

For example, common colds caused by coronavirus have an incubation of about 3.2 days; influenza’s incubation is just under two days, and rhinoviruses (the most common cause of colds) have an incubation of about a day and a half.

Liu and colleagues stressed that the numbers in their study are only averages, and incubation for any one COVID-19 patient could still vary widely. “In this study, the shortest mean incubation reported was 1.8 days and the longest incubation was 18.87 days,” they pointed out.

A shortening of the average incubation period for COVID-19 over time could affect recommendations for self-isolation.

“At present, some countries around the world require close contacts to be isolated for 14 days,” Liu’s group said. “However, with the shortening of the incubation period of new variants, the isolation period can be adjusted appropriately to reduce the pressure on the health system.”

The findings were published in the journal JAMA Network Open.


Source: HealthDay

Study: Half of People Infected With Omicron May Not Have Known It

Steven Reinberg wrote . . . . . . . . .

Are you one of those folks who thinks they have somehow miraculously managed to avoid COVID-19 infection more than two years into the pandemic?

You might be mistaken, claims new research that discovered most people hit by the highly contagious Omicron variant had symptoms so mild they didn’t know they were infected.

A full 56% of those infected weren’t aware they had COVID-19, researchers report. Earlier studies had found that as many as 80% of those infected never experienced symptoms.

“These findings help to confirm what we have suspected for some time, which is that many COVID infections are not being detected or recognized — in part because they are not resulting in a lot of symptoms and in part because there is limited access to or use of diagnostic testing,” said lead researcher Dr. Susan Cheng. She is with the department of cardiology at the Smidt Heart Institute of Cedars-Sinai Medical Center in Los Angeles.

“Most people with COVID being unaware of their infection status, especially while actively transmissible, is likely a major driver of the ongoing pandemic that we are all still trying to make our way through,” she added.

For the study, Cheng’s team took blood samples from health care workers, and in 2021 they were also able to collect blood samples from patients. That part of the study was funded by Sapient Bioanalytics, which tested the samples for the virus.

The researchers had nearly 2,500 health care workers and patients contribute blood samples just before or after the start of the Omicron surge.

They identified 210 people who were infected with the Omicron variant. Only 44% of these people were aware that they had been infected. Of those who were unaware, only 10% said they had symptoms, which they attributed to a common cold or other infection.

“More than half of people who developed Omicron infection were unaware of their infection. In most cases, they had mild or no symptoms. In the few instances where there were mild symptoms, these symptoms were attributed to some other cause, such as a common cold,” Cheng said.

To try to beat the pandemic, it’s vital that people know that they can have COVID-19 and not have any or only mild symptoms, but still spread the infection to others, she stressed.

“Increasing infection awareness could help a great deal to curb the ongoing spread of COVID across our communities,” Cheng said. “Because infection awareness rates appear to be low, there is tremendous room for improvement. We now have the tools to achieve this improvement, and we can each do our part to, hopefully, get through this pandemic faster and together.”

Infectious disease expert Dr. Marc Siegel, a clinical professor of medicine at NYU Langone Medical Center in New York City, said this study clearly shows that COVID-19 has infected many more people than has been reported.

“There’s a heck of a lot more mild or asymptomatic or very, very mildly symptomatic COVID out there than we’re acknowledging, and that means that we’re getting a lot of immunity at least to this variant,” he said. “That might help explain the overall picture of the current state of the pandemic, which is that there’s a lot of mild cases, but there’s also a lot of severe cases.”

Siegel thinks the immunity one gets from the virus has been underplayed.

“It’s especially important now when we’re seeing how easily transmissible this thing is,” he said. “We know we’re undercounting. When I see 100,000 cases a day, I think it’s really a million cases. We’re getting to the point where the vast majority of people in the United States have had COVID in one form or another.”

The combination of immunity from the virus itself and that gotten from vaccination may help slow the pandemic, Siegel said.

Vaccination is important in preventing severe disease, especially among those most at risk. “I’m encouraging patients to get boosted to decrease the risk of hospitalization,” he said.

Soon, Siegel expects to see new vaccines that will be more effective than the current crop, including nasal vaccines and universal coronavirus vaccines.

The report was published online in JAMA Network Open.


Source: HealthDay

New SARS-CoV-2 Variant BA.2.75 Evades All Approved Monoclonal Antibody Therapies

William A. Haseltine wrote . . . . . . . . .

Viral variation has proved to be a critical weak point in our approach to medical solutions for controlling Covid-19. Over the last two and a half years, we’ve seen successive waves of reinfection by new variants of those who’ve been previously infected, those who have been vaccinated and boosted, and those who have been infected, vaccinated, and boosted as well. Behind this unfortunate dynamic is the dramatic variation in the structure of the virus exterior, specifically the Spike protein, which plays a critical role early in infection by binding to the cell surface and forcing entry.

Antibodies that recognize this structure can block infection. However, changes in the exterior structure negate antibody collections in convalescent sera and monoclonal antibodies from binding and neutralizing the virus. A recent study by Yamasoba et al. summarizes the effectiveness of existing monoclonal antibodies against a successive set of virus variants, namely the BA.2 variant, which first emerged in late 2021 and quickly spread around the world, driving the most infectious wave of the virus to date, BA 4/5, which are the predominant strains circulating at the time of writing, and BA.2.75, a new sublineage of BA.2 which is likely more infectious and immune evasive than its predecessors, suggesting it may be the predominant variant in the coming weeks and months.


FIGURE 1: Neutralization assay was performed using pseudoviruses harboring the SARS-CoV-2 Spike … [+] YAMASOBA ET AL.

The ability of the virus to evade natural immunity from the previously infected and vaccinated is also reflected in its ability to escape a host of specific monoclonal antibodies. As is clear from Figure one, the later Omicron viruses evade monoclonal antibodies much more effectively than early strains.

Immediately, we note that five antibodies: adintrevimab, bamlanivimab, casirivimab, etesevimab, and imdevimab failed to neutralize any of the three Omicron sublineages. Casirivimab and imdevimab, as well as etesevimab and bamlanivimab, are designed to be used in tandem in an antibody cocktail, yet their combination antibodies were just as ineffective. Adintrevimab is intended for individual use, meaning its neutralization potency for the strains circulating today is nonexistent. These were among the first monoclonal antibodies developed, rationalizing why they are so ineffective against recent strains.

This leaves five individual monoclonal antibodies. Regdanvimab, sotrovimab, and tixagevimab did not neutralize the previously circulating BA.2 and the currently circulating BA.4/5. However, the three effectively neutralized the BA.2.75 pseudovirus. This suggests that if BA.2.75 became the dominant strain in the coming weeks and months, these three monoclonal antibodies could be effective treatments for those suffering from Covid due to this strain.

Of the two remaining antibodies, cilgavimab poorly neutralized BA.2 and BA.4/5 but was 24.4-fold worse against BA.2.75. Although bebtelovimab effectively neutralized BA.2 and BA.4/5, it again was much worse against BA.2.75, this time 21.2 to 25.6-fold. Despite poorly neutralizing BA.2.75 compared to BA.4/5, bebtelovimab still neutralized the strain better than any other antibody.

Even newer generations of viruses recently detected in South Africa with more extensively mutated Spike proteins, against which bebtelovimab and others may perform even more poorly.

New variants evading monoclonal antibodies should come as no surprise. After infection, the convalescent sera of a recovered patient contains many antibodies designed to inhibit the virus the host just overcame. For the virus to reinfect, it must mutate considerably to evade the convalescent antibodies. Monoclonal antibodies are effectively the same as convalescent antibodies on an individual scale. They are designed to overcome a virus by binding to specific amino acids on the Spike. If the virus mutates enough, the monoclonal antibody can no longer bind. This is how the cat and mouse game of developing antibodies and the virus mutating has continued for two and a half years.

What then can be done? The search is on for monoclonal antibodies that recognize regions of the virus that are critical to the virus lifecycle and therefore are resistant to most mutations. In other words, scientists worldwide are rushing to identify and develop antibodies with broadly neutralizing capabilities, i.e., antibodies that recognize highly conserved sequences of the Spike protein that may overcome all viral variants.

The good news is that many such antibodies have already been identified. We recently described the Cv2.1169 antibody discovered by scientists at the Pasteur Institute and will continue to detail others as data is released. Whether these antibodies recognize and neutralize the latest variants such as BA.2.75 remains an open question.

A second potential solution is to use extensive combinations of functional monoclonal antibodies. While many fail to neutralize, some retain neutralizing capability against the latest variants, and new monoclonal antibodies are constantly advancing. Combining two, three, or four antibodies into a single treatment may suppress infection. Our hope remains high for monoclonal antibodies as a short-term relief for those infected and, in the long run, as a prophylactic against infection in the first place.


Source : Forbes

New Coronavirus Mutant Raises Concerns in India and Beyond

Laura Ungar and Aniruddha Ghosal wrote . . . . . . . . .

The quickly changing coronavirus has spawned yet another super contagious omicron mutant that’s worrying scientists as it gains ground in India and pops up in numerous other countries, including the United States.

Scientists say the variant – called BA.2.75 – may be able to spread rapidly and get around immunity from vaccines and previous infection. It’s unclear whether it could cause more serious disease than other omicron variants, including the globally prominent BA.5.

“It’s still really early on for us to draw too many conclusions,” said Matthew Binnicker, director of clinical virology at the Mayo Clinic in Rochester, Minnesota. “But it does look like, especially in India, the rates of transmission are showing kind of that exponential increase.” Whether it will outcompete BA.5, he said, is yet to be determined.

Still, the fact that it has already been detected in many parts of the world even with lower levels of viral surveillance “is an early indication it is spreading,” said Shishi Luo, head of infectious diseases for Helix, a company that supplies viral sequencing information to the U.S. Centers for Disease Control and Prevention.

The latest mutant has been spotted in several distant states in India, and appears to be spreading faster than other variants there, said Lipi Thukral, a scientist at the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology in New Delhi. It’s also been detected in about 10 other countries, including Australia, Germany, the United Kingdom and Canada. Two cases were recently identified on the West Coast of the U.S., and Helix identified a third U.S. case last week.

Fueling experts’ concerns are a large number of mutations separating this new variant from omicron predecessors. Some of those mutations are in areas that relate to the spike protein and could allow the virus to bind onto cells more efficiently, Binnicker said.

Another concern is that the genetic tweaks may make it easier for the virus to skirt past antibodies — protective proteins made by the body in response to a vaccine or infection from an earlier variant.

But experts say vaccines and boosters are still the best defense against severe COVID-19. In the fall it’s likely the U.S. will see updated formulations of the vaccine being developed that target more recent omicron strains.

“Some may say, ‘Well, vaccination and boosting hasn’t prevented people from getting infected.’ And, yes, that is true,” he said. “But what we have seen is that the rates of people ending up in the hospital and dying have significantly decreased. As more people have been vaccinated, boosted or naturally infected, we are starting to see the background levels of immunity worldwide creep up.”

It may take several weeks to get a sense of whether the latest omicron mutant may affect the trajectory of the pandemic. Meanwhile Dr. Gagandeep Kang, who studies viruses at India’s Christian Medical College in Vellore, said the growing concern over the variant underlines the need for more sustained efforts to track and trace viruses that combine genetic efforts with real world information about who is getting sick and how badly. “It is important that surveillance isn’t a start-stop strategy,” she said.

Luo said BA.2.75 is another reminder that the coronavirus is continually evolving – and spreading.

“We would like to return to pre-pandemic life, but we still need to be careful,” she said. “ We need to accept that we’re now living with a higher level of risk than we used to.”


Source : AP

Dominant Omicron Subvariants Better at Evading Vaccines, Antibody Treatments

The latest omicron subvariants—including the BA.4 and BA.5 forms causing new surges in infections in the United States—are even better at eluding vaccines and most antibody treatments than previous variants, finds a study by researchers at Columbia University Vagelos College of Physicians and Surgeons.

The study, led by David D. Ho, MD, director of the Aaron Diamond AIDS Research Center and the Clyde‘56 and Helen Wu Professor of Medicine at Columbia University Vagelos College of Physicians and Surgeons, was published July 5 in Nature.

Subvariants BA.2.12.1, BA.4, and BA.5 are rapidly expanding worldwide, with BA.4/5 now making up more than 50% of new COVID cases in the United States. These subvariants are thought to be even more transmissible than prior omicron subvariants, owing to several new mutations in spike proteins.

“The virus is continuing to evolve, as expected, and it is not surprising that these new, more transmissible subvariants are becoming more dominant around the world,” says Ho. “Understanding how currently available vaccines and antibody treatments stand up to the new subvariants is critical to developing strategies to prevent severe disease, hospitalizations, and deaths—if not infection.”

In laboratory experiments, Ho and his team studied the ability of antibodies from individuals who received at least three doses of an mRNA vaccine, or got two shots and were then infected with omicron, to neutralize the new subvariants. (Ho’s team did not look at individuals who had not received a booster shot, because a previous study found that two doses provide little protection against infection by earlier omicron variants.)

The study revealed that while BA.2.12.1 is only modestly more resistant than BA.2 in individuals who were vaccinated and boosted, BA.4/5 was at least four times more resistant than its predecessor.

In addition, the scientists tested the ability of 19 monoclonal antibody treatments to neutralize the variants and found that only one of the available antibody treatments remained highly effective against both BA.2.12.1 and BA.4/5.

“Our study suggests that as these highly transmissible subvariants continue to expand around the globe, they will lead to more breakthrough infections in people who are vaccinated and boosted with currently available mRNA vaccines,” Ho says. Though the current study suggests that the new variants may cause more infections in vaccinated individuals, the vaccines continue to provide good protection against severe disease.

“Efforts in the United States to develop new vaccine boosters aimed at BA.4/5 may improve protection against infection and severe disease,” Ho says. “In the current environment, though, we may need to look toward developing new vaccines and treatments that can anticipate ongoing evolution of the SARS-CoV-2 virus.”


Source: Columbia University Irving Medical Center

U.S. Dominant Coronavirus Mutant Contains Ghost of Pandemic Past

Laura Ungar wrote . . . . . . . . .

The coronavirus mutant that is now dominant in the United States is a member of the omicron family but scientists say it spreads faster than its omicron predecessors, is adept at escaping immunity and might possibly cause more serious disease.

Why? Because it combines properties of both omicron and delta, the nation’s dominant variant in the middle of last year.

A genetic trait that harkens back to the pandemic’s past, known as a “delta mutation,” appears to allow the virus “to escape pre-existing immunity from vaccination and prior infection, especially if you were infected in the omicron wave,” said Dr. Wesley Long, a pathologist at Houston Methodist in Texas. That’s because the original omicron strain that swept the world didn’t have the mutation.

The omicron “subvariant” gaining ground in the U.S. — known as BA.2.12.1 and responsible for 58% of U.S. COVID-19 cases last week — isn’t the only one affected by the delta mutation. The genetic change is also present in the omicron relatives that together dominate in South Africa, known as BA.4 and BA.5. Those have exactly the same mutation as delta, while BA.2.12.1 has one that’s nearly identical.

This genetic change is bad news for people who caught the original omicron and thought that made them unlikely to get COVID-19 again soon. Although most people don’t know for sure which variant caused their illness, the original omicron caused a giant wave of cases late last year and early this year.

Long said lab data suggests a prior infection with the original omicron is not very protective against reinfection with the new mutants, though the true risk of being reinfected no matter the variant is unique to every person and situation.

In a twist, however, those sickened by delta previously may have some extra armor to ward off the new mutants. A study released before it was reviewed by other scientists, by researchers at Ohio State University, found that COVID patients in intensive care with delta infections induced antibodies that were better at neutralizing the new mutants than patients who caught the original omicron.

“The omicron infection antibody does not appear to protect well against the subvariants compared to delta,” said Dr. Shan-Lu Liu, a study author who co-directs the viruses and emerging pathogens program at Ohio State.

But Liu said the level of protection a delta infection provides depends partly on how long ago someone was ill. That’s because immunity wanes over time.

People who got sick with delta shouldn’t think of themselves as invulnerable to the new subvariants, especially if they’re unvaccinated, Long said. “I wouldn’t say anyone is safe.”

One bright spot? Booster shots can provide strong protection against the new mutants, Liu said. In general, vaccines and prior infection can protect people from the worst outcomes of COVID-19. At this point, scientists say, it’s too early to know if the new mutant gaining ground in the U.S. will cause a significant uptick in new cases, hospitalizations and deaths.

Scientists are still trying to figure out how virulent these new mutants are. Long said he hasn’t seen anything that answers that question for him, but Liu said emerging data points toward more serious illness. Liu said the subvariants have properties suggesting they spread more efficiently cell-to-cell.

The virus “just hides in the cell and spreads through cell-to-cell contact,” Liu said. “That’s more scary because the virus does not come out for the antibody to work.”

Dr. Eric Topol, head of Scripps Research Translational Institute, said the new mutants certainly don’t appear less virulent than previous versions of omicron, and whether they are more virulent or not “will become clear in the months ahead.”

In the meantime, scientists expect the latest powerhouse mutants to spread quickly, since they are more transmissible than their predecessors.

Though home testing makes it tough to track all U.S. COVID cases, data from Johns Hopkins University shows that cases are averaging nearly 107,000 a day, up from about 87,000 two weeks ago. And new hospital admissions of patients with COVID-19 have been trending upwards since around mid-April, according to the Centers for Disease Control and Prevention.

“I’m hopeful that we don’t see a similar increase in hospitalizations that we’ve had in prior waves,” Long said. “But with COVID, any time you have lots of people being infected, it’s just a numbers game. Some of those people are going to be severe. Some of those people are going to need hospitalization. Some of them, unfortunately, are going to pass away.”


Source : AP

South Africa in New Surge of COVID from Sub-variants of Omicron

Andrew Meldrum wrote . . . . . . . . .

South Africa is experiencing a surge of new COVID-19 cases driven by two omicron sub-variants, according to health experts.

For about three weeks the country has seen increasing numbers of new cases and somewhat higher hospitalizations, but not increases in severe cases and deaths, said Professor Marta Nunes, a researcher at Vaccine and Infectious Diseases Analytics at Chris Hani Baragwanath Hospital in Soweto.

“We’re still very early in this increase period, so I don’t want to really call it a wave,” Nunes said. “We are seeing a slight, a small increase in hospitalizations and really very few deaths.”

South Africa’s new cases have gone from an average of 300 per day in early April to about 8,000 per day this week. Nunes says the actual number of new cases is probably much higher because the symptoms are mild and many who get sick are not getting tested.

South Africa’s new surge is from two variations of omicron, BA.4 and BA.5, which appear to be very much like the original strain of omicron that was first identified in South Africa and Botswana late last year and swept around the globe.

“The majority of new cases are from these two strains. They are still omicron … but just genomically somewhat different,” said Nunes. The new versions appear to be able to infect people who have immunity from earlier COVID infections and vaccinations but they cause generally mild disease, she said. In South Africa, 45% of adults are fully vaccinated, although about 85% of the population is thought to have some immunity based on past exposure to the virus.

“It looks like the vaccines still protect against severe disease,” Nunes said.

Nunes said that the BA.4 and BA.5 strains of omicron have spread to other countries in southern Africa and a few European countries, but it is too early to tell if they will spread across the globe, as omicron did.

The increase in COVID cases is coming as South Africa is entering the Southern Hemisphere’s colder winter months and the country is seeing a rise in cases of flu.

At a COVID testing center in the Chiawelo area of Soweto, many people come in to be tested for COVID, but find out they have flu.

“Now we’re in flu season … so it’s flu versus COVID-19,” said Magdeline Matsoso, site manager at the Chiawelo vaccination center. She said people come for testing because they have COVID symptoms.

“When we do the tests, you find that the majority of them, they are negative when it comes to COVID, but they do have flu symptoms,” said Matsoso. “So they get flu treatment and then they go home because the majority is related to flu and not COVID.”

Vuyo Lumkwani was one of those who came to get tested.

“I wasn’t feeling well when I woke up this morning. I woke up with body pains, a headache, blocked (nose), feeling dizzy, so I decided to come here,” she said.

“I was terrified about my symptoms because I thought it might be COVID-19, but I told myself that I’d be OK because I have been vaccinated,” said Lumkwani. She said she was relieved to be diagnosed with flu and advised to go home with some medications and rest.


Source : AP

BA.4 and BA.5 Variants, Pandemic Fatigue, and Waning Immunity: A Toxic Mix

Kevin Kavanagh wrote . . . . . . . . .

In the beginning of the Omicron surge, the COVID-19 deniers were stating that no one died of the Omicron. At the end of the wave, the United States had more deaths than with Delta.

On Dec. 14, 2021, Infection Control Today® warned in an article entitled “Omicron’s Mild Symptoms Can’t Mask Danger It Poses” that “those who are not vaccinated or immunosuppressed are at risk for severe disease.” On Dec. 20, 2021, Reuters reported that “infections caused by the Omicron variant of the coronavirus do not appear to be less severe than infections from Delta, according to early data from the UK.” Despite the early warnings, reporting on infections being more benign with a lower-case fatality rate continued in most of the news media. This month, a definitive study from Harvard and the Massachusetts General Hospital concluded that the “Omicron variant is as deadly as previous waves after adjusting for vaccinations, demographics, and comorbidities.”

The confusion occurred because Omicron’s case-fatality rates are biased with the inclusion of a large number of vaccinated individuals. If someone concluded that the disease from Omicron was less severe, and thus, they do not need to become vaccinated and protect themselves, then they might have made a fatal error and, at the very least, increased their risk of developing long COVID-19.

For those who have not recently recovered from an infection or let their vaccination immunity wane, their chances of dying or getting long COVID-19 by undertaking a risky activity is far too high. One must remember that even with a low case fatality rate, very high infectivity can overcome the lower virulence by producing a large number of severe cases. Thus, their chances of getting sick during an event is a combination of the infectivity and virulence of the virus; and infectivity increases the chance of severe illness exponentially.

Unfortunately, one’s protection from an infection is not durable. The virus mutates and immune escape variants emerge. This appears to have happened in South Africa with the BA.4 and BA.5 variants. An estimated 90% of the population of South Africa has been exposed to Omicron, and they are still undergoing another surge with the new variants.

BA.4 and BA.5 are thought to be 36% more infectious than the BA.2 Variant and effectively evade immunity. The severity of the disease is not known. Initial reports from South Africa indicate that severity is similar to Omicron; however, the accuracy of reporting from South Africa, similar to Sweden, has come under fire. An article in The Lancet reported South Africa’s excess death rate to be 3.31 times higher than their COVID-19 death rate—one of the highest ratios in the world.

The immediate outlook for the United States warrants concern. Cases are up 25% in the last week with hospitalizations increasing 9%. This increase is fueled by the BA.2 variant and its more infectious offspring, BA.2.12.1. The BA.2.12.1 variant is more infectious than BA.2 and currently comprises 36% of sequenced cases in the United States (as of April 30).

The CDC has also reported the BA.4 and BA.5 variant in 14 states and is likely already in every state in the nation. Although only a few cases have been reported and these variants comprise only a small minority of sequenced cases, individuals need to react now. especially because the United States does not have the best active surveillance system for variants with “some European countries and even South Africa have better sequencing capabilities than the U.S.” Because of these risks, the CDC has restated their recommendation to wear masks on public transportation, and individuals may need to reevaluate the wisdom of holding large events such as the White House Correspondence Dinner. The latter may well be another super spreader event with staff from at least 5 news agencies testing positive for the virus.

Although many individuals measure success by the number who die of COVID-19, the ravages of long COVID-19 are deeply disturbing. The United Kingdom’s Office for National Statistics estimates that 10% to 25% of COVID-19 survivors may develop persistent symptoms. A recent study from the University of Cambridge found that “78% (of patients with long COVID-19) reported difficulty concentrating, 69% reported brain fog, 68% reported forgetfulness, and 60% reported problems finding the right word in speech.” Further, COVID-19 causes impairment similar to what occurs between the ages of 50 to 70, equivalent to losing 10 IQ points.

From Dec. 2021 to Feb. 2022, the seroprevalence in the United States from SARS-CoV-2 infections was 58%. Since that time, many more infections from Omicron have occurred. In addition, 66% of the United States citizens are currently “fully vaccinated.” Thus, almost everyone in the United States has had some exposure to SARS-CoV-2. If herd immunity can be achieved, then the United States should have achieved it. If another surge occurs, unfortunately, those numbers may be the status quo.

With new variants emerging, cases rising and a more complete understanding of the dangers of long COVID-19, one can make a strong case for resuming public health measures intended to control spread and infections from this disease. Unfortunately, even in the face of waning immunity, few individuals in the United States are currently wearing masks, and many are continuing to engage in risky behavior. This may well be a toxic mix, and healthcare facilities, and infection preventionists need to prepare for another possible surge in cases.


Source : Infection Control Today