Why mixed vaccines can help boost immunity
We should have a better idea soon. Some trials are currently underway to test the efficacy of the vaccine combination, and the first results will be released later this month. If these hybrid solutions prove to be safe and effective, countries will be able to keep the vaccine launched even if the supply of a vaccine is reduced due to manufacturing delays, unforeseen shortages or safety issues.
But there is another more exciting prospect that may become an important part of our future strategy: the mixed vaccine may lead to a wider immunity and hinder the virus’ attempts to evade our immune system. Ultimately, mashups may be the best way to protect yourself.
The covid-19 vaccine currently in use protects against the virus in a slightly different way. Most of the spike proteins that target coronaviruses, which are used to enter our cells. But some provide instructions for producing protein in the form of messenger RNA (Pfizer, Moderna). Some provide the spike protein itself (Novavax). Some people use another harmless virus in the manufacturing instructions to transport it, such as a Trojan horse (Johnson & Johnson, Oxford-AstraZeneca, Sputnik V). Some provide complete inactivated viruses (Sinopharm, Sinovac).
in a Research published in MarchResearchers from the State Food and Drug Administration of China tested a combination of four different covid-19 vaccines in mice and found that some of them did improve the immune response. When they first provided rodents with a vaccine, which relied on a harmless cold virus to be smuggled in the instructions, and then vaccinated with a different type of vaccine, they saw higher antibody levels and better T cell response. However, when they changed the order and placed the virus vaccine in second place, they did not see improvement.
Shan Lu, a physician and vaccine researcher at the University of Massachusetts Medical School, said that why combined injections can improve efficacy is a bit mysterious. He is the pioneer of this hybrid strategy. “We can partially explain the mechanism, but we don’t fully understand it yet.” Different vaccines provide the same information in slightly different ways. These differences may awaken different parts of the immune system or enhance the immune response. This strategy can also make immunity last longer.
Whether these results will translate to humans remains to be seen. Researchers at the University of Oxford have conducted a human trial to test the hybrid working method. The study, called Com-CoV, provided participants with the first photos of Pfizer or Oxford AstraZeneca. For the second dose, they will get the same vaccine or an injection of Moderna or Novavax. The first result should be available in the next few weeks.
Other research is also in progress. In Spain, where Oxford AstraZeneca is now only available to people over 60, researchers plan to recruit 600 people to test whether the injection dose of the first injection can be used with Pfizer’s second injection. According to a report by El País, about 1 million people received the first dose of the vaccine, but they were not old enough to receive the second dose. Health officials are waiting for the results of this study before issuing recommendations to the team, but it is not clear whether any participants were recruited.
In the second half of last year, Oxford-AstraZeneca announced that it would cooperate with the Gamaleya Institute in Russia, which has developed a satellite V vaccine to test how the two vaccines can be combined. The trial was originally scheduled to start in March and provide interim results in May, but it is unclear whether it actually started. Chinese officials have hinted that they will explore mixed vaccines to improve the effectiveness of injections.
The biggest benefit may come from the less effective mixed vaccine. Pfizer and Moderna’s mRNA vaccines provide excellent protection. Donna Farber, an immunologist at Columbia University, said: “I don’t think there is a reason to worry about it.” But mixed use may increase the protection of some vaccines that have reported lower levels of protection, such as Oxford-AstraZeneca and Johnson & Johnson, and certain Chinese vaccines. Many of these vaccines work well, but mixing them may help them work better.