'High Protection' From 2 Doses of Pfizer Vaccine
Two doses of the Pfizer/BioNTech COVID-19 vaccine provided more than 95% protection against infection, hospitalisation, severe illness, and death, according to a
study in The Lancet. based on Israel's experience up to 3 April.
Israel was the first country to report national data on the Pfizer vaccine based on its nationwide vaccination campaign. Adjusted estimates of vaccine effectiveness at 7 days or longer after the second dose were:
- 95·3% against SARS-CoV-2 infection
- 91·5% against asymptomatic infection
- 97·0% against symptomatic COVID-19
- 97·2% against COVID-19-related hospitalisation
- 97·5% against severe or critical COVID-19-related hospitalisation
- 96·7% against COVID-19-related death
Vaccine effectiveness was seen across all age groups, and against the B.1.1.7 variant that was predominant at the time of the investigation.
Comment: The figures above seem very much in line with the corresponding results of the Phase 3 RCT trial for this vaccine. The 91% figure might suggest an estimate of the percentage effectiveness against transmission (on the basis that those without asymptomatic infection ab initio cannot transmit a virus with which they aren't infected). This figure is much higher than the assumptions in the SPI-M papers taken by SAGE, and would mean that:
1) The third wave peak is likely to be much lower than feared.
2) UK herd immunity is a realistic and achievable goal.
Both the above depend on no VoC emerging with either a higher transmissibility rate or vaccine evasion, or both.