How effective have booster doses been in containing the spread of coronavirus 

Although booster doses have reduced fatalities considerably, their impact on containing the spread of infection has varied across geographies.

In the last week of January 2021, the United States was reporting an average of 1.6 lakh Covid cases a day. The daily fatality number was close to 3,300. Following the vaccination rollout, the country witnessed a drop in cases and deaths in the months that followed.

The relief was short-lived. The number of cases began to rise again in the country in the last week of August and stayed at an elevated level of nearly 1.5 lakh a day in the better part of September. The daily death count averaged around 1,700 for the whole of September. That was also the time of booster doses.