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The World Health Organization's director of immunization, vaccination, and biologics argues it may be too early to push for population-level COVID-19 booster shots, especially when many people around the world have not even received their first dose.

There just isn't enough evidence right now to back up the need for widespread boosters in heavily vaccinated countries, director Kate O'Brien suggested in an interview with Stat News. Looking specifically at the two-dose mRNA vaccines produced by Pfizer and Moderna, O'Brien said the timing and rationale for third doses isn't really about "boosting," anyway. Instead, "it's actually about whether ... you need a third priming dose" for people who are immunocompromised. "For some vaccines ... there seems to be evidence coming forward, more about people who are having a failure of the primary series [of shots] and evidence on whether or not a third priming dose would help," she said.

With that in mind, a "much more important message" than whether all fully immunized folks need to get a booster is that "we have really have huge inequity right now in just getting primary doses to people," O'Brien continued. 

"The focus [of Covid vaccination] really is on reducing serious disease, hospitalizations, and death," she said. "And when you look at the deployment of the vaccines globally, a whole lot of those vaccines have gone to people who have extremely low risk of that happening, while at the same time there are huge numbers of people who do fall into that risk group who haven't been vaccinated. We're just really out of kilter here." Read O'Briens full interview at Stat News.