If the doses of coronavirus vaccinations are delayed, the chances of a vaccine-resistant strain of Covid-19 will be increased, government scientists have warned.
In new reports, issued by the Scientific Advisory Group for Emergency (Sage), experts also warned that resistant new variants are a ‘realistic possibility’ driven by the virus that responds to increasing levels of natural immunity among the population.
The government’s decision to delay the second dose of vaccines instead of three to 12 weeks, to try to protect more people against the virus, has sparked outrage among frontline health workers who fear they are at greater risk due to infections.
There are also proposals from Israel, which have yet to be fully ratified, that the protection against a first dose may be much less than originally thought.
In papers released Friday, Sage scientists said there was an “increased risk of viral replication under partial immunity after one dose than after two doses. Therefore, a delay in the second dose would be expected in the short term to reduce the likelihood of emergence of the vaccine will increase slightly.resistance – but probably from a low base.
‘Is such a propagating material? It is currently not possible to quantify the likelihood of emergence of vaccine resistance due to the delayed second dose, but it is likely to be small. The UK currently has more than 1,000 Covid-19 deaths per day and has a limited amount of vaccine.
“In the current UK circumstances, the unquantifiable but probably small probability of the delayed second dose, which generates a vaccine escape mutant, must be weighed against the measurable benefits of doubling the rate at which the most vulnerable protection can be obtained by vaccine. . ”
But the newspaper added: ‘Given what we have recently observed with variants B.1.1.7 and B1.351, it is a realistic possibility that over time immune flight variants will emerge, probably driven by increasing population immunity to natural infection. ”
It warned: “The vaccine efficacy after one dose should be closely monitored to inform future vaccine policies.”
Sir Patrick Vallance, chief scientific adviser, said at a press conference in Downing Street on Friday that the virus would probably be “forever”, adding: ‘The most risky thing in terms of new mutation is getting a very high to have appearance. The more the virus is transmitted and repeated between people, the more likely it is to get a mutation, and this is what is happening around the world. This is the biggest risk.
“There is always a risk if you start getting partial immunity, but there is also an advantage that partial immunity can stop the infection faster.”
Chris Whitty, the chief adviser to the government, said: “The whole medicine is about balancing risks. Our general view was that the balance of risks was in favor at this stage of the UK epidemic that many more people needed to be vaccinated, but that meant a delay. The specific risk was a much smaller risk of not getting people vaccinated, which was the alternative. ‘
All viruses mutate and natural variations in the Sars-CoV-2 virus have been identified worldwide and according to the Sage newspaper, it is likely to occur at a faster rate as larger numbers of people become immune to infection.
It added: “Most mutations are unimportant, but some may happen to offer a functional advantage over others and by natural selection may become a dominant laboratory-generated variant.”
It is said that there is ‘theoretical and experimental data supporting the possibility’ that the virus could generate new variants that would ‘evade’ antibody therapies, recovery plasmas and vaccines, as well as natural immunity.
The paper says that vaccinated people who have developed Covid-19 must genetically sequester their virus “as quickly as possible to understand whether viral variation can explain the breakthrough”.
Increased sequence of tests will help identify new clusters and spot changes as they occur after the vaccine explodes.