The UK’s National Health Service has pushed back the window for people to receive the second dose of the COVID-19 vaccine made by Pfizer and BioNTech – at a time that companies have only tested on a small percentage of patients.
The NHS has written a letter to hospitals saying those expected to receive their second dose after Jan.4 should be postponed from three weeks until 12 noon, with most recipients booked in the last week of that period. The move would bring the window of the schedule closer to the recently approved vaccine manufactured by the University of Oxford and pharmaceutical company AstraZeneca AZN,
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The NHS said the move would protect the most people at risk in the shortest time frame and have the greatest impact on mortality.
Confirmed cases of the coronavirus have increased over the past month, with the UK saying a new variant of the virus responsible for COVID-19 is more easily transmitted. Daily cases increased from 12,330 at the end of November to 50,023 on December 30.
When the UK Medicines and Health Products Regulatory Agency gave emergency approval for the vaccine from US pharmaceutical company Pfizer PFE,
and its German partner BNTX,
he said the interval between doses should be at least three weeks and was based on analyzes including patients who received their second vaccination within 19 to 42 days of their first vaccination.
Pfizer said the vaccine’s safety and efficacy had not been tested in the new interval. “The Pfizer and BioNTech Phase 3 study for the COVID-19 vaccine was designed to assess the safety and efficacy of the vaccine on a 2-dose schedule, separated by 21 days. The safety and efficacy of the vaccine has not been evaluated over different dosage regimens because the majority of trial participants received the second dose within the window specified in the study design, ”the company said.
Pfizer also noted that there is no evidence that protection is maintained 21 days after receiving the first dose.
“While decisions on alternative dosing regimens are the responsibility of health authorities, Pfizer believes it is essential that health authorities conduct surveillance efforts on any other schedules implemented and ensure that each recipient receives maximum protection. possible, which means vaccination with two doses of the vaccine ”. Pfizer said. A message left with BioNTech was not immediately returned.
In the briefing that the drug companies provided to the U.S. Food and Drug Administration, they said about 80% of patients who received the second dose administered it within 10 weeks of receiving of the first.