Yesterday an article in The Lancet provided an independent scientific assessment of the need for COVID-19 vaccine booster doses. The publication reviewed the current data on booster vaccines, which generally shows very good efficacy even with the Delta variant for the mRNA based vaccines from Pfizer and Moderna.
The general tone of the article suggested that current efficacy is more than adequate to avoid infection, but more importantly, effectively prevents severe illness causing hospitalization or death.
This publication generated a fair amount of political commentary since two of the authors, Philip Krause and Marion Gruber, were senior vaccine review officials at the FDA that have had recently resigned from the agency. This was reportedly due to a disagreement with the Biden administration’s push for vaccine boosters. But that discussion was really a distraction from the central message surrounding of this publication.
The real point of the article was that, “Current evidence does not appear to show a need for boosting in the general population, in which efficacy against severe disease remains high.” The authors relate this to the fact that antibody immunity, which is what is usually measured in the blood, is not central to protection from severe disease. “This protection could be because protection against severe disease is mediated not only by antibody responses, which might be relatively short lived for some vaccines, but also by memory responses and cell-mediated immunity, which are generally longer lived.”
More importantly, the authors of this article believed, “The limited supply of these vaccines means they will save the most lives if made available to people who are at appreciable risk of serious disease and have not yet received any vaccine. Even if some gain can ultimately be obtained from boosting, it will not outweigh the benefits of providing initial protection to the unvaccinated.”
Of interest, reports of the article by the New York Times and the WSJ presented the conclusions without comment, however a prior editorial in the WSJ took the opposite tack arguing for boosters. This prompted me to review the potential benefits for booster vaccines, especially given these shots would appear to have little risk given the safety of vaccine’s first and second doses (although this has not been proven yet).
Most of the data on booster vaccine benefits comes from Israel, where the population was immunized early on with the Pfizer vaccine. The data has been reported to suggest the booster has been effective in blunting the recent Delta variant driven surge in COVID-19 cases. However, this data only reflects a few weeks of activity after the boosters have been given, so we don’t know the long term benefit. Importantly, cases are falling dramatically in both those with only two vaccine doses and those with boosters, so the benefit of the booster isn’t clear.
What is driving the current, Delta driven surge in infections is also interesting. The number of people hospitalized is greatest in the U.S., which is due to its overall low vaccination rate. But it is interesting to see the UK and Israel with high numbers, given they are thought to be highly vaccinated.
It turns out though, that Israel has a much lower rate of vaccination than most people think, especially compared to other developed countries.
So again, it is the unvaccinated who are driving this surge, not individuals with two vaccine doses who need a booster.
Bottom line, if you want a third, booster vaccine shot, and it is available, you can have it with little risk. But the only way to stop the current surge is to vaccinate the people without any vaccine coverage! That is the real message from the Lancet publication.