The first dose of the Pfizer vaccination is 85% effective against coronavirus infection between two and four weeks after inoculation, according to a study published in the Lancet medical journal. The pharmaceutical giant and its German partner BioNTech, meanwhile, have told the U.S. Food and Drug Administration that their vaccine can be safely stored at standard freezer temperatures, which, if approved by the FDA, could help facilitate faster distribution by negating the need for expensive deep-freeze storage.
The Israeli survey was carried out on healthcare workers at the largest hospital in the country, which on December 19 launched a mass vaccination campaign regarded as the world's fastest.
Israeli studies have found the Pfizer vaccine to be 95% effective one week after a second jab, while the Lancet report focused on more than 9,000 medical staff at Sheba hospital near Tel Aviv. Some 7,000 of them received the first dose and the rest were not inoculated.
From the group, 170 were diagnosed with COVID-19 after tests carried out only on those showing symptoms or who had been in contact with coronavirus carriers. Fifty-two percent of them were found to have not been vaccinated. Comparing the two groups, the Sheba study calculated that the vaccine was 47% effective between one and 14 days after inoculation, rising to 85% after 15 to 28 days.
"What we see is a really high effectiveness already right after two weeks, between two weeks to four weeks after vaccine, already high effectiveness of 85% reduction of symptomatic infection," Gili Regev-Yochay, co-author of the study, told a small group of journalists.
He said that despite the vaccine being "amazingly effective," scientists are still studying whether fully vaccinated people can transmit the virus to others.
"That is the big, big, question. We are working on it. This is not on this paper and I hope we will have some good news soon," said Regev-Yochay.
So far trial data on only one major vaccine in use around the world, the Oxford University/AstraZeneca shot developed in the U.K., shows efficacy at preventing asymptomatic infection, indicating it could also help to curb transmission.
Pfizer and BioNTech announced their submission of research data on storage temperatures to the FDA in a joint statement on Friday.
The FDA's Emergency Use Authorization for the vaccine, issued months ago, stipulates that it be stored at temperatures well below zero (-112ºF to ‑76ºF), which requires special equipment for both transport and storage at health care facilities. Under the companies' new recommendation, the vaccine could be stored for up to two weeks at standard freezer temperatures of -13°F to 5°F, "as an alternative or complement to storage in an ultra-low temperature freezer."
"We have been continuously performing stability studies to support the production of the vaccine at commercial scale, with the goal of making the vaccine as accessible as possible for healthcare providers and people across the U.S. and around the world," Pfizer CEO Albert Bourla said in the Friday statement announcing the request to the FDA to change its guidance. "We appreciate our ongoing collaboration with the FDA and CDC as we work to ensure our vaccine can be shipped and stored under increasingly flexible conditions. If approved, this new storage option would offer pharmacies and vaccination centers greater flexibility in how they manage their vaccine supply."
"The data submitted may facilitate the handling of our vaccine in pharmacies and provide vaccination centers an even greater flexibility," added BioNTech CEO and Co-founder Ugur Sahin. "We will continue to leverage our expertise to develop potential new formulations that could make our vaccine even easier to transport and use."
The other vaccine approved for use and already widely circulating in the U.S., made by Moderna, also currently requires deep-freeze storage and transport under FDA's usage guidelines. The Oxford/AstraZeneca vaccine only requires refrigeration at standard temperatures, which makes it far easier to move around and store, but that shot has not yet been given the greenlight for use in the U.S.