ZURICH - Vaccines from AstraZeneca, Russia’s Gamaleya Institute and Johnson & Johnson fight the coronavirus with another virus, leaving scientists concerned the shots may lose potency if annual inoculations become necessary to fight new variants.
Most vector-vaccine developers have opted to use an adenovirus, a harmless class of common-cold viruses.”The experience with adenoviruses has been for many years that vectors can be intercepted by the immune system after repeat injections,” said Bodo Plachter, deputy director of the Institute of Virology at Mainz University’s teaching hospital.
Moderna as well as Pfizer and partner BioNTech said in separate statements this week they are studying additional booster shots that target new variants over time. But vector immunity has been implicated in past failures, including when a 2004 Merck AIDS vaccine trial flopped in men previously exposed to the adenovirus used for the vaccine.
It's the same for flu vaccines, where yearly innoculations are required.
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