Many countries around the globe are starting to roll out another booster of the COVID-19 vaccine but, with public interest waning and a sense of normalcy firmly installed in our minds, this may prove an ill-fated effort, unless authorities can provide a coherent answer to the question “Is another jab really needed?” (The short answer is a firm “yes,” of course.)
In what we could call the “chronic” phase of the pandemic, most countries have now settled for a certain number of daily cases and a (relatively low) number of complications and deaths. It’s the vaccines that have afforded us this peace of mind, lest we forget. But they are different to other vaccines that we are more familiar with, such as the MMR that we get as kids and then forget about for the rest of our lives. As good as the different COVID-19 vaccines are, they never came with the promise of generating lifelong antibodies. We knew early on that the immunity they provide slowly wanes with time. That doesn’t mean that those who have their vaccination records up to date (which included a booster probably earlier in 2022) are suddenly exposed. Data suggest that although people several months past their last booster would now be more prone to getting reinfected, the protection against severe disease still hangs around 85%. In other words, their chances of ending up in the hospital are low.
Why worry, then, about further boosting the immune system? The same studies show that an additional jab would increase this percentage up to 99%. Is this roughly 10% improvement really worth another worldwide vaccination campaign? Well, this is a numbers game, after all. The current form of the virus is extremely infectious, and the Northern Hemisphere is heading toward the cold months of the year, which we have seen in past years increases COVID-19 contagions, as you would expect from any airborne virus. Thus, it’s easy to expect a new peak in the number of cases, especially considering that we are not going to apply any of the usual restrictions to prevent this. In these conditions, extending the safety net to a further 10% of the population would substantially reduce the total number of victims. It seems like a good investment of resources.
We can be more surgical about it and direct this new vaccination campaign to the population most likely to end up in the hospital. People with concomitant pathologies are at the top of the list, but it’s also an age issue. On the basis of different studies of the most common ages of admission, the cutoff point for the booster varies from country to country, with the lowest being 50 and in other cases hovering around 65 years of age. Given the safety of these vaccines, if we can afford it, the wider we cast the net, the better, but at least we should make every effort to fully vaccinate the higher age brackets.
The final question is which vaccine to give. There are confounding studies about the importance of switching to Omicron-specific jabs, which are finally available. Although this seems like a good idea, since Omicron infections elicit a more effective range of antibodies and new variants seem to better escape our defenses, recent studies suggest that there actually may not be so much difference with the old formula.
The conclusion? This regimen of yearly boosters for some may be the scenario for the upcoming years, similar to what we already do for the flu, so we should get used to it.
Dr. Macip is associate professor, department of molecular and cellular biology, University of Leicester (England). He reported no relevant conflicts of interest.
A version of this article first appeared on Medscape.com.