COVID-19 vaccine manufacturers have been repeating for months: two doses are better than one.The U.S. Centres for Disease Control and Prevention (CDC) study found that a single dose of the Pfizer-BioNTech or Moderna vaccine is 64 per cent effective against hospitalizations in adults over 65 years of age.
That number leaps to 94 per cent at least 14 days after a second dose of the same vaccines.The small-scale study surveyed 417 older adults in 24 hospitals spread across 14 states.Yet it provides more real-world evidence of what had already been proven in clinical trials for both the Pfizer and Moderna vaccines, which found very similar results to the CDC study.