Pfizer's Covid vaccine may only be 42% effective against the Indian 'Delta' variant, Moderna's 76%

The two most commonly used COVID-19 vaccines in the U.S. may not be as effective against the Indian 'Delta' variant, a new study finds. Pfizer's vaccine efficacy dropped to 42% in July, with Moderna's falling down to 76%, when the Delta variant became the dominant strain. Hospitalizations among vaccinated people remained low despite an increase in cases, though with both vaccines more than 75 percent effective against hospitalization. The FDA may soon start allowing Americans to receive vaccine booster shots to shore up protection against virus