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COVID19: Delaying second dose of vaccine increases risk of new resistant strain, Sage papers reveal

Warning over ‘realistic possibility’ of resistant strains of the virus emerging

London, Jan 23: Delaying doses of coronavirus inoculations will increase the chances of a vaccine-resistant strain of Covid-19 emerging, scientists have warned.

In new reports, released by the Scientific Advisory Group for Emergencies (Sage), experts also warned that resistant new variants were a “realistic possibility” driven by the virus reacting to increasing levels of natural immunity among the population.

In papers released on Friday, Sage scientists said there was an “increased risk of virus replication under partial immunity after one dose than after two doses, so in the short term, delaying the second dose would be expected to somewhat increase the probability of emergence of vaccine resistance – but probably from a low base.

“Is such an increase material?

It is not currently possible to quantify the probability of emergence of vaccine resistance as a result of the delayed second dose, but it is likely to be small.

“In the current circumstances the unquantifiable but likely small probability of the delayed second dose generating a vaccine escape mutant must be weighed against the measurable benefits of doubling the speed with which the most vulnerable can be given vaccine-induced protection.”

But the paper added: “Given what we have observed recently with the variants B.1.1.7 and B1.351, it is a realistic possibility that over time immune escape variants will emerge, most likely driven by increasing population immunity following natural infection.”It warned: “Vaccine efficacy after one dose should be carefully monitored to inform future vaccine policy.”

Sir Patrick Vallance, the chief scientific adviser, told a Downing Street press conference on Friday that the virus was likely to be around “forever”, adding:

The most risky thing in terms of new mutation is to have very high prevalence. The more the virus is transmitting and replicating between people the more likely it will get a mutation, and that is what is happening around the world”.

That’s the biggest risk.

There is always some risk if you start to have partial immunity, but there is also a benefit which is partial immunity can actually stop the infection quicker.”

Chris Whitty, the U.K government’s chief medical adviser, said:

“All of medicine is about balance of risk. Our overall view was that the balance of risk was firmly in favour at this stage of the epidemic in the UK of having many more people vaccinated but that does mean a delay. That particular risk was a much smaller risk of not having people vaccinated which was the alternative.”

All viruses mutate and natural variations in the Sars-CoV-2 virus have been identified across the globe and the Sage paper said this was likely to happen at a “faster rate” as greater numbers of people become immune after infection.

It added: “Most mutations will be inconsequential, but a few may, by chance, confer a functional advantage over others and, through natural selection may become dominant laboratory-generated variants.”

It said there was “theoretical and experimental data supporting the possibility” that the virus could generate new variants which would “evade” antibody therapies, convalescent plasma, and vaccines as well as natural immunity.

The paper said vaccinated people who went on to develop Covid-19 need to have their virus genetically sequenced “as quickly as possible to understand whether viral variation may explain the breakthrough”.

Increased sequencing of tests would help identify new clusters and spot changes as they emerge after the vaccine rollout.

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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.

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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

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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.”

AGENCY

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