The Pfizer/BioNTech vaccine appears to give high protection against asymptomatic Covid-19, according to data from Israel – a finding that will boost hopes that mass vaccination can stop the spread of the virus.
The top line of the real-world results, issued by the Israeli ministry of health and the companies but not yet peer-reviewed by scientists, is efficacy of 97% against disease and death and 94% against infection without symptoms.
Israel is the first country to have vaccinated more than half its population, which it has done with the collaboration of Pfizer/BioNTech and an agreement to monitor the results. As of Wednesday, about 55% of its 9 million population had been given at least one dose of the Pfizer vaccine, according to health ministry data, and 43% had received a second dose, which in Israel takes place three weeks after the first.
Last month a paper from Israel’s largest health provider, published in the New England Journal of Medicine, said the vaccine appeared to have 94% efficacy against symptomatic illness and 92% against severe disease.
The companies declined to release the finer details of the results, on the grounds that they will be published in a peer-reviewed journal in due course. But Pfizer said the data confirmed the 95% efficacy it had found in its phase 3 trials of the vaccine, called BNT162b2, and pointed to the role the vaccine could play in stopping the virus spreading.
“The findings which suggest that the vaccine may also provide protection against asymptomatic Sars-CoV-2 infections are particularly meaningful as we look to disrupt the spread of the virus around the globe,” said Luis Jodar, the chief medical officer at Pfizer Vaccines.
“Altogether, these data are critical to understanding the role of vaccination in combating the pandemic and provide hope to other countries dealing with this devastating disease, which has now afflicted the world for more than a year.”
Ugur Sahin, the chief executive of BioNTech, said: “The real-world data reported from Israel demonstrate that BNT162b2 is exceptionally effective in fighting Sars-CoV-2. Our vaccine has been effective in preventing ovid-19 cases, as well as profoundly reducing the rate of Covid-19-related severe diseases, hospitalisations and deaths.”
He said the findings were also important because the data was generated at a time when the Sars-CoV-2 variant B117 – known as the UK or Kent variant because of where it emerged – was the dominant strain. B117, which is highly transmissible, was responsible for 80% of tested cases in Israel during the study period. It now accounts for about 98% of cases in the UK and is also common around the world.
However, the data shed no light on the effects of the vaccine against variants that have emerged in South Africa and Brazil, because there have been few cases of either in Israel.
Prof Yeheskel Levy, the director of the Israeli health ministry, said the impact of vaccination had been profound. “Incidence rates in the fully vaccinated population have massively dropped compared to the unvaccinated population, showing a marked decline in hospitalised cases due to Covid-19,” he said.
“This clearly demonstrates the power of the Covid-19 vaccine to fight this virus and encourages us to continue even more intensively with our vaccination campaign. We aim to achieve even higher uptake in people of all ages, which gives us hope of regaining normal economic and social function in the not so distant future.”