Question: My friend insists he doesn’t need the vaccine because he’s already been infected.  Is previous infection as protective as vaccination?

Answer: No, previous infection is not nearly as protective as vaccination.  In fact, earlier this week CDC’s MMWR published a study on this very topic, Reduced Risk of Reinfection with SARS-CoV-2 After COVID-19 Vaccination — Kentucky, May–June 2021.  Study authors used a case-control design to explore whether vaccination reduced the risk of reinfection.  Basically, they identified individuals in Kentucky ages 18+ who had originally been infected in 2020 and were subsequently reinfected in May-June 2021 (cases) and compared them with a similar group of people who had originally been infected in 2020, but had not been reinfected as of end-June 2021 (controls).  To improve the comparison, they matched cases and controls by sex, age, and date of original infection.  In so doing, they found “Kentucky residents who were not vaccinated had 2.34 times the odds of reinfection compared with those who were fully vaccinated (odds ratio [OR] = 2.34; 95% confidence interval [CI] = 1.58–3.47). These findings suggest that among persons with previous SARS-CoV-2 infection, full vaccination provides additional protection against reinfection. To reduce their risk of infection, all eligible persons should be offered vaccination, even if they have been previously infected with SARS-CoV-2.”  Please keep talking to your friend about the benefits of vaccination– for him and all of us!