19 February 2021
A Correspondence piece from The Lancet provides data from Israel on symptomatic COVID-19 infection in healthcare workers following the administration of the first dose of the Pfizer/BioNTech vaccine. In response, the British Society for Immunology has released the following statement:
Professor Deborah Dunn-Walters, Chair of the British Society for Immunology COVID-19 and Immunology Taskforce and Professor of Immunology at the University of Surrey, said:
“Due to the high percentage of the Israeli population vaccinated so far, we have been awaiting data from there to indicate the first signs of how effective COVID-19 vaccines are outside of a clinical trial setting and how dosing schedule plays into this. These data on a good sample size of over 9,000 people show that the Pfizer/BioNTech vaccine is 85% effective in stopping symptomatic disease at 15-28 days after the first dose. This is certainly promising.
“The timescale over which effectiveness is measured in this study (at 15-28 days) is important. The immune response generated by any vaccine takes approximately 10-14 days to develop the all-important immune memory that stops us getting sick if we come in contact with the real virus. Studies that look at infection rates from 0-14 days after the first dose of a vaccine are not very informative as we know that the immune system is building its memory at this time and protection will not yet be up to maximum power.
“It should be noted that this study was carried out on people of working age, so it will be informative to see a similar study in older people after one dose. Although further research is needed, overall these new findings should provide reassurance around the UK’s decision to offer the two doses of the vaccine 12 weeks apart.
“While the results of this study show that a good level of immunity is present after one dose of the Pfizer/BioNTech vaccine, it is still the case that the highest and longest lasting protection from getting ill with COVID-19 will only be provided by getting two doses of the vaccine. It is critical that all people eligible for COVID vaccination do return to get their second dose when asked to do so by their medical providers.”