Focus on the memory cells
Dr. Offit wrote in the editorial: “Arguably, the most disappointing error surrounding the use of COVID-19 vaccines was the labeling of mild illnesses or asymptomatic infections after vaccination as ‘breakthroughs.’ As is true for all mucosal vaccines, the goal is to protect against serious illness – to keep people out of the hospital, intensive care unit, and morgue. The term ‘breakthrough,’ which implies failure, created unrealistic expectations and led to the adoption of a zero-tolerance strategy for this virus.”
Dr. Offit said that the focus should be on the memory cells, not the neutralizing antibodies.
Regarding mRNA vaccines, Dr. Offit said “the surprise of this vaccine – it surprised me and other vaccine researchers – is that with these two doses of mRNA separated by 3-4 weeks, you actually appear to have long-lived memory response.
“That’s not the history of vaccines. If you look at the inactivated polio vaccine or the inactivated hepatitis A vaccine, you really do need a 4- to 6-month interval between doses to get high frequencies of memory cells. That doesn’t appear to be the case here. It looks like two doses given close together do just that. Memory cells last for years if not, sometimes, decades.”
Neutralizing antibodies, on the other hand, protect against mild illness and their effectiveness wanes after months.
“At some point we are going to have to get used to mild illness,” Dr. Offit said.
The Centers for Disease Control and Prevention must now determine who will benefit most from booster dosing and educate the public about the limits of mucosal vaccines, Dr. Offit wrote in the editorial.
“Otherwise, a zero-tolerance strategy for mild or asymptomatic infection, which can be implemented only with frequent booster doses, will continue to mislead the public about what COVID-19 vaccines can and cannot do.”
The work was funded by the Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute.
A version of this article first appeared on Medscape.com.