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More and more is being said about mixing vaccines against COVID-19. Research on the effects of such a procedure is also ongoing. The results of the work of scientists from South Korea have just been published. The researchers looked at the protection provided by vaccination with AstraZeneka first and then with Pfizer (as a second dose). The results are very optimistic. Moreover, this isn’t the only study that brings good news about the benefits of mixing vaccines.
- South Korean study: people vaccinated first with AstraZeneka and then with Pfizer had levels of neutralizing antibodies six times higher than those who were fully vaccinated with AstraZeneka alone
- Earlier study from Germany: volunteers vaccinated with Pfizer or in a combination regimen developed about 10 times more antibodies than those who received two doses of AstraZeneka
- The Pfizer vaccine significantly enhanced the antibody responses in those vaccinated with AstraZeneka
- The combination of AstraZeneca and BioNTech-Pfizer seems to be a promising way to immunize people against COVID-19
- You can find more about COVID-19 vaccinations on the Onet homepage.
Mixing COVID-19 Vaccines. The «AstraZeneca – Pfizer» package – what are the effects?
499 employees of the medical sector participated in the study. Two hundred people were vaccinated against COVID-19 using two doses of Pfizer / BioNTech, one hundred people received a mixed package of vaccines – they were vaccinated first with AstraZeneka, and the second dose was given the Pfizer vaccine. The remaining volunteers took both doses of AstraZeneka. Reuters reported on the results of the work of South Korean scientists.
All participants in the study developed neutralizing antibodies after vaccination, which prevent the virus from entering the cells and replicating. The levels of these antibodies in those vaccinated with the two different preparations were similar to those vaccinated with Pfizer alone and six times higher than those given two doses of AstraZeneca.
As Reuters notes, similar results were obtained in a survey conducted in June by the British. It turned out that vaccination with AstraZeneka first and then with Pfizer gave a stronger immune response than the administration of these preparations in the reverse order.
- Vaccines protect against Delta? One may be less effective
The Korean Disease Control and Prevention Agency (KDCA) also reported that the study looked at the immune response of vaccinated people to variants of the coronavirus. As it turned out? None of the three groups showed reduced neutralizing activity against the variant Alpha (former British mutation). However, for the Beta, Gamma, and Delta variants (first detected in South Africa, Brazil and India, respectively), neutralizing antibody levels were reduced by 2,5 to six times.
Mixing COVID-19 Vaccines. 10 times more antibodies
It is worth mentioning the earlier study on the effects of the combined AstraZeneca vaccine pack (first dose) – Pfizer (second dose). They were carried out at the Saarland University Hospital in Hamburg on 250 volunteers. The participants were divided into three groups: the first group received two doses of AstraZeneca, the second group also received two doses, but of the Pfizer vaccine. The third group of participants received one dose of both vaccines: first they were given a dose of AstraZeneka, then of Pfizer.
After two weeks, the researchers looked at the subjects’ immune responses. As it turned out? Both the double dose of the Pfizer vaccine and its combination with AstraZeneki were significantly more effective than the double dose of the AstraZeneca vaccine. Volunteers vaccinated with Pfizer or in the mixed regimen developed about 10 times more antibodies than those who received two doses of AstraZeneka.
- Also read: Side effects of COVID-19 vaccines [COMPARISON]
– We not only looked at the number of anti-coronavirus antibodies, but also the effectiveness of the so-called neutralizing antibodies – explained Prof. Martina Sester, specialist in transplantology and immunology of infections at the University of Saarland. “This tells us how well the antibodies prevent the virus from entering our cells,” she added.
– In terms of antibody development, the Pfizer dual vaccine and the AstraZeneca-Pfizer combination vaccine were significantly more effective than the AstraZeneki dual vaccine. And looking at neutralizing antibodies, the results from the two types of vaccination were even slightly better than those obtained after two BioNTech injections, Sester described.
«Increased responses» after mixing vaccines against COVID-19
The Spanish CombivacS study, conducted on 663 participants at the Carlos III Health Institute in Madrid, led to similar conclusions. The preliminary results of the research have been published in the scientific journal Nature. Like the results from Saarland University, they are not yet finally confirmed – the publication in Nature is an overview of what scientists in Spain have discovered so far, not a full peer-reviewed article.
- Also read: Are there groups of patients who should not be vaccinated with AstraZeneca?
Magdalena Campins, a CombivacS researcher at Vall d’Hebron University Hospital in Barcelona, reported that those who received the full combination of the mix-and-match vaccine, a dose from Pfizer and Astra Zeneka, began producing significantly higher levels after the second vaccination. antibodies, and these antibodies were able to recognize and deactivate SARS-CoV-2 in laboratory tests.
“The Pfizer vaccine appears to have greatly enhanced the antibody responses in AstraZeneki single-dose vaccines,” commented Nature Zhou Xing, an immunologist at McMaster University in Hamilton, Canada.
Do you want to test your COVID-19 immunity after vaccination? Have you been infected and want to check your antibody levels? See the COVID-19 immunity test package, which you will perform at Diagnostics network points.
Mixing vaccines. How it’s working?
AstraZeneca is a traditional vector vaccine. It uses a harmless version of the virus to instruct human cells to learn to build antibodies against the coronavirus. The Pfizer vaccine, on the other hand, is an mRNA vaccine that uses a new type of immunization method. MRNA vaccines ‘teach’ human cells to make a protein that in turn triggers an immune response and the production of antibodies.
Scientists do not yet have enough information to know why combining the two vaccines may result in increased immunity. Professor Sester said she was looking forward to more research into combining different types of vaccines and their interactions. ‘We believe that if other research teams come to a similar conclusion to ours, the combination of vector and mRNA vaccines should be seriously considered,’ she said.
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