BioNTech, the German biotech group behind the first approved Covid-19 vaccine, warned there was “no data” to support plans to delay the second dose of the jab with the aim of reaching as many people as possible with limited supplies.
Germany is considering following the UK in delaying second doses amid growing concern over a more infectious variant of the virus, which emerged in England.
The Germans health ministry confirmed to the Financial Times that it had asked the country’s vaccination commission “to review and evaluate the available data and studies and to issue a recommendation on this issue”.
However, the European Medicines Agency told the FT that the BioNTech/Pfizer vaccine — the only shot currently approved for use by the regulator in the EU — had been authorised as two injections, given at least 21 days apart, and that diverging from this regimen would require separate authorisation.
“Any change to this would require a variation to the marketing authorisation as well as more clinical data to support such a change, otherwise it would be considered as ‘off label use’,” the EMA said.
The US Food and Drug Administration is also convinced that the vaccination programme should not be changed without another clinical trial. It warned that changing Covid-19 vaccine doses and schedules could be “counterproductive” and pose public health risks.
“Without appropriate data supporting such changes in vaccine administration, we run a significant risk of placing public health at risk, undermining the historic vaccination efforts to protect the population from Covid-19,” said Stephen Hahn, FDA commissioner, and Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, in a joint statement on Monday.
Germany’s move came after Britain chose to extend the timeline for the second dose of vaccines from BioNTech/Pfizer and Oxford/AstraZeneca from three or four weeks to up to three months.
BioNTech said its trials, run with US pharmaceutical group Pfizer, were largely based on two doses administered roughly three weeks apart and that this remained the recommended advice.
“[The] safety and efficacy of the vaccine has not been evaluated on different dosing schedules as the majority of trial participants received the second dose within the window specified in the study design,” the Mainz-based company told the FT.
BioNTech’s comments echoed those of its partner Pfizer, which also called the UK decision into question last week by restating the recommended 21-day period between doses.
Data from the companies’ phase-3 trials, which involved more than 43,000 people in six countries, demonstrated that participants gained partial protection from the vaccine as early as 12 days after the first dose. But the study did not show how long that protection lasted, as participants received their second shot nine days later.
A review in the New England Journal of Medicine, published last month, found that between the first and second doses, the group that received the vaccine had fewer than half the number of infections than the group that received the placebo.
Those results suggest an efficacy rate of 52 per cent after the first dose, which was higher than the protection level required for a Covid-19 vaccine by the US regulator.
The UK’s four chief medical officers, including England’s Chris Whitty, have defended the decision to extend the recommended gap between the first and second dose from 21 days to up to three months.
“We have to ensure that we maximise the number of eligible people who receive the vaccine,” the officials said in a joint statement last week.
The rapid spread of a new mutant strain of Sars-Cov-2 in the UK has encouraged some scientists in other countries to back Britain’s approach.
Akiko Iwasaki, professor of immunobiology at Yale University, said that while she remained a proponent of the two-dose schedule, “given the urgency, we can delay the second dose until more vaccines become available”.
“It was the B.1.1.7 variant transmission rate that did it for me,” Prof Iwasaki wrote on Twitter, referring to reports that the new strain was at least 50 per cent more transmissible.
Thomas Mertens, the head of Germany’s vaccine committee, told DPA news agency last week that extending the gap between doses was “definitely worth considering”. The country is also exploring whether it can extract six doses from each vial of the BioNTech/Pfizer vaccine, rather than the five currently recommended by the manufacturers.
Some scientists have warned that extending the interval between first and second doses could increase the risk of vaccine-resistant mutations, if the virus is then transmitted between millions of people who are partially but not fully protected against infection.
“Delay in second dosing may contribute to this risk,” said Deenan Pillay, professor of virology at University College London and a member of Independent Sage, a UK group of scientists who offer an alternative view to the UK government’s official advisers. “But I understand the public health argument for making the first doses a priority, since we are in a complete emergency with our hospitals overwhelmed.”
Additional reporting by Donato Paolo Mancini in Rome and Hannah Kuchler in New York
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