Worrisome new coronavirus variants can evade antibodies that neutralize original virus
(Asian News Hub) – New research at Washington University School of Medicine in St. Louis indicates that three new, fast-spreading variants of the virus that cause COVID-19 can evade antibodies that work against the original form of the virus that sparked the pandemic.
With few exceptions, whether such antibodies were produced in response to vaccination or natural infection, or were purified antibodies intended for use as drugs, the researchers found more antibody is needed to neutralize the new variants.
The findings, from laboratory-based experiments and published March 4 in Nature Medicine, suggest that COVID-19 drugs and vaccines developed thus far may become less effective as the new variants become dominant, as experts say they inevitably will. The researchers looked at variants from South Africa, the United Kingdom and Brazil.
“We’re concerned that people whom we’d expect to have a protective level of antibodies because they have had COVID-19 or been vaccinated against it, might not be protected against the new variants,” said senior author Michael S. Diamond, MD, PhD, the Herbert S. Gasser Professor of Medicine.
“There’s wide variation in how much antibody a person produces in response to vaccination or natural infection. Some people produce very high levels, and they would still likely be protected against the new, worrisome variants. But some people, especially older and immunocompromised people, may not make such high levels of antibodies. If the level of antibody needed for protection goes up tenfold, as our data indicate it does, they may not have enough. The concern is that the people who need protection the most are the ones least likely to have it.”
The virus that causes COVID-19, known as SARS-CoV-2, uses a protein called spike to latch onto and get inside cells. People infected with SARS-CoV-2 generate the most protective antibodies against the spike protein.
Consequently, spike became the prime target for COVID-19 drug and vaccine developers.
The three vaccines authorized by the Food and Drug Administration (FDA) for emergency use in the U.S. — made by Pfizer/BioNTech, Moderna and Johnson & Johnson — all target spike. And potent anti-spike antibodies were selected for development into antibody-based drugs for COVID-19.
Viruses are always mutating, but for nearly a year the mutations that arose in SARS-CoV-2 did not threaten this spike-based strategy. Then, this winter, fast-spreading variants were detected in the United Kingdom, South Africa, Brazil and elsewhere.
Sparking concern, the new variants all carry multiple mutations in their spike genes, which could lessen the effectiveness of spike-targeted drugs and vaccines now being used to prevent or treat COVID-19. The most worrisome new variants were given the names of B.1.1.7 (from the U.K.), B.1.135 (South Africa) and B.1.1.248, also known as P.1 (Brazil).
To assess whether the new variants could evade antibodies made for the original form of the virus, Diamond and colleagues, including first author Rita E. Chen, a graduate student in Diamond’s lab, tested the ability of antibodies to neutralize three virus variants in the laboratory.
The researchers tested the variants against antibodies in the blood of people who had recovered from SARS-CoV-2 infection or were vaccinated with the Pfizer vaccine.
They also tested antibodies in the blood of mice, hamsters and monkeys that had been vaccinated with an experimental COVID-19 vaccine, developed at Washington University School of Medicine, that can be given through the nose.
The B.1.1.7 (U.K.) variant could be neutralized with similar levels of antibodies as were needed to neutralize the original virus. But the other two variants required from 3.5 to 10 times as much antibody for neutralization.
Then, they tested monoclonal antibodies: mass-produced replicas of individual antibodies that are exceptionally good at neutralizing the original virus. When the researchers tested the new viral variants against a panel of monoclonal antibodies, the results ranged from broadly effective to completely ineffective.
Since each virus variant carried multiple mutations in the spike gene, the researchers created a panel of viruses with single mutations so they could parse out the effect of each mutation.
Most of the variation in antibody effectiveness could be attributed to a single amino acid change in the spike protein. This change, called E484K, was found in the B.1.135 (South Africa) and B.1.1.248 (Brazil) variants, but not B.1.1.7 (U.K.).
The B.1.135 variant is widespread in South Africa, which may explain why one of the vaccines tested in people was less effective in South Africa than in the U.S., where the variant is still rare, Diamond said.
“We don’t exactly know what the consequences of these new variants are going to be yet,” said Diamond, also a professor of molecular microbiology and of pathology & immunology.
“Antibodies are not the only measure of protection; other elements of the immune system may be able to compensate for increased resistance to antibodies.
That’s going to be determined over time, epidemiologically, as we see what happens as these variants spread. Will we see reinfections? Will we see vaccines lose efficacy and drug resistance emerge? I hope not.
But it’s clear that we will need to continually screen antibodies to make sure they’re still working as new variants arise and spread and potentially adjust our vaccine and antibody-treatment strategies.”
The research team also included co-corresponding author Ali Ellebedy, PhD, an assistant professor of pathology & immunology, of medicine, and of molecular microbiology at Washington University; and co-corresponding author Pei-Yong Shi, PhD, and co-first author Xianwen Zhang, PhD, of the University of Texas Medical Branch.
Washington University School of Medicine
Serosurvey would determine impact of possible 3rd Covid wave on children: DAK
(Asian News Hub) – Doctors Association Kashmir (DAK) on Saturday said serosurvey of pediatric population in the valley would determine the impact of possible third Covid-19 wave on children.
Serosurvey of children will give us a fair estimate of their vulnerability in predicted third wave,” said DAK President and influenza expert Dr Nisar ul Hassan.
“Serosurvey involves testing blood samples of individuals for antibodies that are developed after an infection,” he said.
“This will give us an idea about the percentage of pediatric population who might have developed natural immunity.”
Dr Hassan said recently, a serosurvey of general population including children aged 7 to 17 years has been completed in Kashmir, the results of which are awaited. The sample size per district in the age group 7 to 11 was 40 and it was 80 in 12-17 age group.
“The survey needs to be extended to the age group of 0 to 6 years and the sample size per district should be 500 to 1000 to get a clearer picture of the actual percentage of children who have developed immunity against Covid-19,” he said.
Dr Hassan said there are speculations that children would be affected more than adults in possible third wave as this is the population group in which there is no vaccine yet.
“However, various serosurveys have dismissed the claim that the next wave will be affecting children exclusively,” he said.
“A pediatric serological study conducted by AIIMS, New Delhi at five different sites found that 55.7 percent children had developed antibodies,” DAK President said.
“The study found that seroprevalence of children and adults in the same regions were almost similar.”
“Another study conducted by PGI Chandigarh revealed that 69 percent of children had antibodies against Covid-19,” he said.
“These children had remained either asymptomatic or mildly symptomatic during the infection.”
“The data of the two surveys prove that children have acquired natural immunity against the virus and it is highly unlikely that the third wave will affect children more than adults,” said Dr Nisar.
“This is a big relief. Because the apprehensions expressed by several health experts about the third wave primarily targeting children had left people worried,” he said.
“But, we can’t derive conclusions on the data from other regions. We need to have our own data based on which decisions can be made ahead of the feared third wave,” he added.
Israel reports Pfizer COVID-19 vaccine effectiveness against infection down to 40%
(Asian News Hub) – The Health Ministry said Thursday that the effectiveness of the Pfizer COVID-19 vaccine in preventing infection and mild symptoms has dropped to 40%, according to new data collected over the past month as the delta variant spreads in Israel.
In a televised address, Prime Minister Naftali Bennett meanwhile called on Israelis who haven’t been vaccinated to do so as soon as possible.
“The Israeli government is investing billions so that there is a vaccine available in every location in the country, and there are still a million Israelis who simply refuse to be vaccinated,” he said. “The vaccine refusers are endangering their health, their surroundings and all Israeli citizens. If a million Israelis continue to be unvaccinated, this will force the others to shut themselves in at home.”
The effectiveness of the vaccine in preventing hospitalizations and severe symptoms stands at 88% and 91%, respectively, the ministry said.
With inputs from Haaretz
Scientists discover more than 30 viruses frozen in ice, most never seen before
(Asian News Hub) – A group of scientists discovered ancient viruses frozen in two ice samples taken from the Tibetan Plateau in China, and most of them are unlike anything ever seen before.
The findings, published Wednesday in the journal Microbiome, came from ice cores taken in 2015 that scientists said began to freeze at least 14,400 years ago.
“These glaciers were formed gradually, and along with dust and gases, many, many viruses were also deposited in that ice,” Zhi-Ping Zhong, lead author and researcher at the Ohio State University Byrd Polar and Climate Research Center, said in a statement. “The glaciers in western China are not well-studied, and our goal is to use this information to reflect past environments. And viruses are a part of those environments.”
When researchers analyzed the ice, they found genetic codes for 33 viruses. Of the 33, genetic codes for four of them showed they are part of virus families that typically infect bacteria. Up to 28 were novel, meaning they had never before been identified.
The group said it doesn’t believe the viruses originated from animals or humans but came from the soil or plants. The scientists said roughly half of them survived because of the ice.
“These are viruses that would have thrived in extreme environments,” said Matthew Sullivan, co-author of the study and director of Ohio State’s Center of Microbiome Science.
“These viruses have signatures of genes that help them infect cells in cold environments – just surreal genetic signatures for how a virus is able to survive in extreme conditions.”
Sullivan said the technology used to study microbes and viruses inside the ice would lead to looking for similar genetic sequences in other extreme ice environments, possibly on Mars.
Senior author of the study Lonnie Thompson said the discovery of the viruses in glaciers of ice will help researchers understand how they respond to climate change.
“We know very little about viruses and microbes in these extreme environments and what is actually there,” Thompson said.
“The documentation and understanding of that is extremely important.”
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