Fully vaccinated people who get a breakthrough case of COVID-19 may be less infectious than their unvaccinated peers because vaccinated people don’t shed the virus as long, according to new research.

The study, published online this week in the New England Journal of Medicine, involved NBA players, their families and staff. It found that vaccinated people who got COVID-19 cleared the virus from their systems two days sooner than the unvaccinated. On average, vaccinated people cleared the virus in 5½ days while the unvaccinated took 7½ days.

Between November 2020 and August 2021, researchers worked with the National Basketball Association to analyze 19,941 viral samples from 173 people registered in the professional league’s occupational health program. NBA players were subjected to COVID-19 testing on a regular basis as part of the program.

“This allowed us to uncover what infections look like in the very early stages. Usually, we only see the virus once a person has symptoms, when they’re at peak,” study co-author Stephen Kissler said, reported by USA TODAY.

According to the study, there was no difference between individuals who received the two-dose Pfizer-BioNTech mRNA vaccination and those who received the one-dose Johnson & Johnson viral vector vaccine. Due to the insufficient sample size, Moderna’s mRNA vaccine was not evaluated.

Previous studies have found that vaccinated people are less likely to be infected in the first place, and, on average, experience shorter, milder symptoms if infected.

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