Could the three month dosing interval enable coronavirus to outwit vaccines?

Over the last week or so, I’ve been posting about vaccination policy and coronavirus mutations, and these subjects are now becoming more inter-related. This morning on BBC Breakfast, a care home manager was talking about the fact that he knew of examples of elderly residents in care homes around the country catching covid -19 after having their first vaccine in December, some of whom have died. He called for the original vaccine protocol to be restored for care home residents, ie the second dose to be administered three weeks after the first dose.

Mass vaccination centre in Birmingham

This calls into question a number of issues, including the wisdom and efficacy of the Government’s delayed second dose policy, or whether the first dose is sufficient to protect against the new UK variant of coronavirus, or the other known mutations (South Africa and Brazil).

I came across another issue in the journal “Science”, where virologists worry that millions of people with only partial immunity could be a potential breeding ground for vaccine-resistant mutations, as they wait for their second dose. They worry that lengthening the dosing interval from 3 weeks to 3 months could speed the emergence of such mutants by creating a pool of sub-immune people who have enough antibodies to slow the virus and avoid developing symptoms—but not enough to wipe it out. 

Of course, many experts don’t agree on how big of a risk a long delay between doses poses, especially when weighed against the current out-of-control spread of the pandemic in many places. “It’s carnage out there,” says Andrew Read, an evolutionary microbiologist at Pennsylvania State University, University Park. “Twice as many people with partial immunity has got to be better than full immunity in half of them.”

However, with an infinite number viral replications occurring every second, the chance of mutations to occur is very high as the virus makes errors in copying its genetic alphabet. The South African variant has evolved two mutations that block the effectiveness of antibodies used to treat COVID-19, raising the spectre that they could also block vaccine-induced antibodies. click full article

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