Researchers did not provide separate estimates for the naturally immune and unvaccinated, and the vaccinated and infected, against hospitalization and death.

Authorities have shifted to promoting them as a tool to prevent severe disease, but that protection has also become subpar against Omicron and its subvariants, real-world data and studies show.

Researchers did not provide an estimate of effectiveness for a primary series or boosters among the population against hospitalization and death.

“Our study showed that the additional benefits of vaccination were similar between previously infected and previous uninfected children,” Dan-yu Lin, a professor in the University of North Carolina’s Department of Biostatistics, told The Epoch Times via email.

The study did not evaluate vaccine safety or COVID-19 symptoms and Lin declined to provide evidence for the risk-benefit statement.

It’s actually three doses ( pdf), because a two-dose regimen didn’t induce an adequate immune response, according to Pfizer.