Previous Covid Prevents Delta Infection Better Than Pfizer Shot

People who recovered from a bout of COVID-19 during one of the earlier waves of the pandemic appear to have a lower risk of contracting the delta variant than those who got two doses of the vaccine from Pfizer Inc. and BioNTech.

The largest real-world analysis comparing natural immunity -- gained from an earlier infection -- to the protection provided by one of the most potent vaccines currently in use showed that reinfections were much less common. The paper from researchers in Israel contrasts with earlier studies, which showed that...