British health officials will now allow people to mix COVID-19 vaccines as the pandemic flares up – but experts warn it could be risky.
The change in vaccine advice, which comes as the country faces a new highly contagious mutation in the virus, marks a surprising departure from previous guidelines – and a completely different approach to vaccine launch in the US, the New York Times reported.
The UK protocol now states that a person can receive COVID-19 follow-up with a candidate vaccine other than the first dose, if necessary.
The UK has approved two vaccines for the deadly bug, developed by AstraZeneca and Pfizer.
“For persons who have started the program and are participating in vaccination in a place where the same vaccine is not available or if the first product received is not known, it is reasonable to provide a dose of the locally available product to complete the program”, the updated statements guidance.
However, the protocol reiterates that it is preferable to receive a second dose of the same vaccination, noting that a different inoculation should only be used if the patient is at “immediately high risk” or is considered “unlikely to participate again”.
Under these conditions, because both vaccines are based on spike protein, it is likely that the second dose will help increase the response to the first dose, she explained.
But the new advice has still raised eyebrows in the scientific community.
“There is no data on this subject,” Cornell University vaccine expert John Moore told the Times, adding that British officials “seem to have completely abandoned science and are just trying to figure out how to get out of the mess.”
The update is also in contrast to the guidelines set by the US Centers for Disease Control and Prevention, which explicitly state that vaccines “are not interchangeable.”
“Any of the vaccines currently authorized with COVID-19 mRNA can be used when indicated,” the CDC wrote, noting that the Advisory Committee on Immunization Practices “does not mention a product preference.”
However, these COVID-19 mRNA vaccines are not interchangeable with each other or with other COVID-19 vaccine products, the agency said. “The safety and efficacy of a number of mixed products have not been evaluated.”
The CDC goes on to say that if different doses of vaccines are given “by mistake”, then no extra doses of any vaccine should be given.
When contacted by The Post, the CDC declined to comment on the UK’s updated guidelines and whether it would re-evaluate its guidelines in light of the new advice.
The United States has signed two coronavirus vaccines, developed by Pfizer and Moderna.
The UK, which has surpassed 2.5 million confirmed cases of COVID-19, is battling the rise in infections as a more contagious variant sweeps across the country – prompting at least 17 countries to announce British travel bans.