With the new guidelines following reports of rare blood clots, the global medical community is considering whether it is possible and safe to administer two different candidates to the same person.
This week, the European Medicines Agency and the UK Agency for Medicines and Health Products established that there is a possible link between the AstraZeneca-Oxford University vaccine and very rare cases of unusual blood clots with low blood platelets.
Neither the European nor the UK authorities have recommended age restrictions on the use of the vaccine. However, the UK regulator noted that the data suggest that there is a slightly higher incidence compared to younger adult age groups and therefore recommends that this evolving evidence be taken into account when taking consider the use of the vaccine.
The EMA similarly reiterated that the vaccine is safe and effective, but noted that the use of the vaccine at national level will also take into account the pandemic situation and the availability of the vaccine in each country.
Subsequently, the United Kingdom, various EU countries and other governments around the world decided to recommend the use of alternative vaccines for young people.
Given the change in orientation, young people are now asking: If I have already received a dose of vaccine, should I go back for a second?
Governments have different answers to this question. Health experts generally agree that mixing and fitting vaccines should be safe. But clinical trials are ongoing.
Orientation varies
The UK Joint Committee on Vaccination and Immunization recommends: “Everyone who has received a first dose of AstraZeneca COVID-19 vaccine should continue to be given a second dose of AstraZeneca COVID-19 vaccine, regardless of age. The second dose will be important for longer protection against COVID-19. “
Instead, the French health regulator recommends that people under the age of 55 who received the first dose of AstraZeneca receive Pfizer or Moderna for the second blow. It recommends a gap of 12 weeks between these first and second photos in these cases. The regulator said there was no reason to fear specific adverse events if you had the first AstraZeneca jab and then switched to an mRNA jab for the second.
Germany has followed a similar path. The German Committee for Vaccines recommended that people under the age of 60 who had received a single injection of AstraZeneca jab opt for a different vaccine for the second dose.
The Prime Minister of Baden-Wuerttemberg, Winfried Kretschmann (R), received the AstraZeneca vaccine against the new coronavirus in Stuttgart, southern Germany, on March 19, 2021.
MARIJAN MURAT AFP | Getty Images
Ongoing processes
“Guidelines are guidelines. But, as a core immunologist, can I see any argument as to why it would be an unsafe or poor practice to mix and match vaccines? No, I can’t see at all. It would, however, induce high immunity. There is no problem with that, “Danny Altmann, a professor of immunology at Imperial College London, told CNBC’s” Squawk Box Europe “on Friday.
Andrew Freedman, a reader of infectious diseases at Cardiff University School of Medicine, told CNBC: “Studies are underway to look at the concept of mix and match. There is no theoretical reason why this should not. be feasible and safe, but we have to wait for these studies. “
Regarding a possible booster dose that may be needed in the fall or winter, he added: “I don’t think there is any real concern that you might not be able to follow two doses of AstraZeneca vaccine with one of the other messenger RNA vaccines. ”
Meanwhile, Franz-Werner Haas, CEO of vaccine maker CureVac, told CNBC this week: “The good news is that all of these vaccines encode the same spike protein … so there are clinical trials and data that you can mix and match. fit these different vaccination platforms. ”
“So in this regard, I have high hopes that this will work quite well,” he added.
CureVac’s own candidate is still in clinical trials. Reading the data is on track for the second quarter of this year.
The Centers for Disease Control and Prevention claims that the safety and efficacy of a number of mixed products have not been evaluated.
Several studies are underway to analyze the effects of vaccine mixing. The UK launched a study in February, specifically looking at mixing the AstraZeneca-Oxford vaccine with the Pfizer-BioNtech vaccine. The results are not expected to be available until the summer. Separately, studies are being conducted on a combination of AstraZeneca-Oxford vaccines and the Russian Sputnik V vaccine.