Vaccine Table Update: May 5, 2021

Okay, lots of vaccine info coming in. Here is the updated Table (changes from last iteration are in peach). Details are below.


  • Real world effectiveness is 76.7% among patients in the Mayo Clinic Health system between February 27th and April 14th, 2021. Unfortunately, the virus was not sequences, so we don’t know which variant these patients had. But fantastic news, nonetheless (source here)


  • In the Phase II trial in South Africa, 49% efficacy in HIV+ and HIV- participants (here)

  • Efficacy in HIV-negative participants was 60% and did not differ by presence of antibodies at baseline (here)

  • Interestingly, authors found that among the placebo group, prior natural infection provided no protection against COVID19 when infected with the B.1.351 variant (here)

  • Enrollment open for pediatric study (press release here)


  • Continues to look good against B.1.1.7 (here)

  • Is not looking good against B.1.351, resulting in a very low efficacy rate (here)


I’ve noticed, with Pfizer, that research findings are starting to get repetitive. This means that we are getting closer and closer to the “true” rates of efficacy and transmission reduction.

  • Efficacy

    • Looks good against B.1.1.7 (Qatar study showed 87-90%)

    • Looks good against B.1.351 (Qatar study showed 72-75%)

  • Protection from hospitalization

    • United States: Real world effectiveness against hospitalizations is lower than clinical trials (95% vs 100%), but not by much. Looking great. (here)

    • Israel: Among 4.5 million people, vaccine led to 97% reduction in hospitalization (here)

  • Protection from death

    • In Qatar, there were 1,616 breakthrough cases out of 265,410 (0.6%) people vaccinated with two doses. Among those breakthrough cases, there were 2 COVID19 related deaths.

    • In Israel, among 4.5 million people, the vaccine led to 97% reduction in COVID19 related deaths (here)

  • Transmission reduction

    • 86% lower incidence of asymptomatic infection more than 7 days after the second dose in a retrospective cohort of healthcare workers in Israel (here)

    • Vaccine effectiveness is 92% against asymptomatic infection in Israel

    • In the United States, vaccinated had a 72% lower incidence of asymptomatic infection (here)