We should have a better idea soon. Several major tests are now underway to test the strength of the vaccine combination with the first results later this month. If these mixed measures are proven safe and effective, countries will be able to keep this vaccine rollout afloat even if the supply of a vaccine is declining due to production delays, unforeseen crises or safety concerns.
But there is another exciting possibility that could be a vital part of our strategies in the future: mixing vaccines increases broad-based immunity and can hinder our efforts to survive the virus. In the end, the best way to protect yourself is to mix and match methods.
Being mixed in the test
The Covid-19 vaccine currently used protects against the virus in a slightly different way. Most target the spike protein of the coronavirus, which it uses to enter our cells. Some, however, provide instructions for making proteins in the form of Messenger RNA (Pfizer, Modarna). Some supply the spike protein itself (Novavax). Some people use other innocent viruses to ferry with instructions like Trojan horses (Johnson & Johnson, Oxford-AstraZeneca, Sputnik V). Some provide complete inactivated viruses (Synoform, Synovac).
In this The research was published in March, Researchers at the National Food and Drug Administration in China tested a combination of four different Covid-19 vaccines in rats and found that some were able to boost immunity. They improved antibody levels and observed T-cell responses when they first relied on innocent cold viruses for trafficking in rats instructions and then gave a second dose of a different type of vaccine. But when they reversed the order and gave the viral vaccine a second chance, they saw no improvement.
Shane Lu, a physician and vaccine researcher at the University of Massachusetts Medical School, says the combination of shots may improve the effectiveness of the combination. “The process that we can partially explain, but we don’t fully understand.” Different vaccines present the same information in slightly different ways. These differences can awaken different parts of the immune system or sharpen the immune response. This can further prolong the strategy.
It remains to be seen whether these results translate to humans. Researchers at Oxford University have launched a human experiment to test exactly how the mixture might work. Pfizer or Oxford-AstraZeneca first shots were provided to participants in this study, known as low-CV. For their second dose, they will receive either the same vaccine or a shot Moderna or NovaVax. The first results should be available in the coming weeks.
Other studies are also underway. In Spain, where Oxford-AstraZeneca is now only being given to people over the age of 60, researchers plan to recruit people to test whether the first dose of the shot can be combined with a second dose of Pfizer. According to El Paso, about ten million people received the first dose of the vaccine but are not old enough to receive the second dose. Health officials are waiting for the results of the study before making recommendations for the group, but it is not yet clear if any participants have been recruited.
Late last year, Oxford-AstraZeneca announced they would partner with Russia’s Gamalia Institute, which developed the Sputnik V vaccine, to test how the two shots would work together. The trial is set to begin in March and end in May. And Chinese officials have indicated they will search for mixed vaccines to increase the effectiveness of their shots.
The biggest benefits are that vaccines may be less effective than mixtures. Pfizer and Moderner mRNA vaccines provide great protection. “I don’t think there’s a cause for concern,” said Donna Farber, an immunologist at Columbia University. The mixture, however, may improve the safety of a few vaccines that offer lower levels of protection, such as Oxford-Astrageneca and Johnson & Johnson, as well as some Chinese vaccines. Many of these vaccines work quite well but the combination helps them work better.