The first coronavirus vaccine to be authorized in Europe, developed by Pfizer and BioNtech laboratories, has the particularity of being inoculated in two doses three weeks apart.
The United States will respect the recommendations resulting from the clinical trials of manufacturers, explained Dr. Anthony Fauci. This is not the strategy adopted by the United Kingdom, which is facing a more contagious variant of the Covid – 18, nor that of Denmark, who chose to delay the second injection in order to vaccinate, even partially, a larger number of people.
According to Public Health England, the British public health agency, the effectiveness of the vaccine is 89% 15 at 21 days after the injection of the first dose. It goes up to 92% after the second injection.
Is there a risk of reducing the effectiveness of vaccine from Pfizer and BioNTech against Covid – 18 by delaying the injection of the second dose? If both laboratories recommend carrying out the second injection 20 days after the first, several countries chose to postpone the injection of this second dose in order to provide even partial coverage to a greater number of their citizens.
This is notably the strategy adopted by the United Kingdom, where vaccinated people can wait until 12 weeks before receiving the second dose, and in Denmark, where this period may be extended to six weeks. Germany could also adopt this strategy.
BioNTech posted a warning Monday, warning that “the efficacy and safety of the vaccine has not been evaluated for other dosing schedules.” The efficacy of the vaccine is 42% 12 at 20 days after the injection of the first dose, according to Public Health England, the English agency public health, cited by the British Medical Journal . It goes up to 92% after second injection, based on clinical trial data.
In a context where the demand for the vaccine currently exceeds the delivery capacities, several specialists have looked into that question. Experts from the WHO Immunization Group recommend to administer the second dose “within 20 at 28 days ”, but that this could be delayed“ in exceptional circumstances of epidemiological contexts and supply constraints ”. Kate O’Brien, director of the “immunization and vaccination” department of the international organization, warned, however, that this delay could not exceed six weeks.
In the United States, Dr. Anthony Fauci, director of the National Institute of Allergies and Infectious Diseases, has indicated Jan. 1 in an interview with CNN that his country would follow recommendations from clinical trials. Monday, it was the turn of the FDA to recommend to follow the recommendations of the manufacturers. The federal body, responsible for authorizing the marketing of drugs, warns that a change in the administration of the second dose, whether for the Pfizer vaccine or that of Moderna, which has just been approved by the European Medicines Agency and also requires a second dose after 27 days, is “premature” and “is not firmly anchored in the available evidence ”.
The European Medicines Agency recommends not to exceed 6 weeks
The agency American adds that 98% of participants in Pfizer-BioNTech vaccine clinical trials and 89% of those of po tests ur Moderna vaccine received a dose after respectively 20 or 28 days, not allowing to know what would be the effectiveness of the first dose beyond these times.
The European Medicines Agency, for its part, recommends not to back down injection of the second dose beyond 28 days (six weeks), reports the Reuters news agency.
Debate between doctors in the United Kingdom
In the United Kingdom, the decision is debated. An association of British doctors underlined several difficulties created by this postponement, including that of reorganizing appointments for elderly patients.
Independent SAGE, a group of doctors organized as a response to the scientific committee which advises the British government, however supports this change, underlining that the vaccination campaign begin
while a new variant of the Covid – 19 se spread in the country . This is “substantially more transmissible” than the earlier variants. The pandemic is “out of control” and the British health system, the NHS, “is in trouble”, they stress. The vaccination of a large number of people, as well as another battery of measures, such as restrictions on movement, are, according to this group, the weapons to limit the spread of the new variant.