When a vaccine does its job, it will produce a strong immune response in the patients who are involved with it – the body is forced to make antibodies to the disease in question. However, different groups of people may respond differently to each given vaccine.
In the case of COVID-19, it is especially important that a vaccine is able to generate antibodies well in older people, as they often suffer less severe outcomes when they are infected with the new coronavirus.
Thursday brought some positive news on that front: Pfizer (NYSE: PFE) en BioNTech (NASDAQ: BNTX) showed that its leading candidate for coronavirus vaccine, BNT162b2, appears to generate anti-antibodies in its research generations at higher concentrations than those found in patients recovering from COVID-19.
In a Phase 1 clinical trial, after receiving two doses of BNT162b2, participants in the 18 to 55 age group had antibody levels 3.8 times higher than those found in recovering patients. The 65- to 85-year-olds in the study did not produce as many antibodies as the younger population, but their antibody levels were still 1.6 times those found in recovering patients.
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The study also tested a second vaccine candidate named BNT162b1, but Pfizer and BioNTech found that BNT162b2 elicits a more robust immune response because it produces a longer viral protein. BNT162b2 also causes side effects less often than BNT162b1, which causes redness and swelling at the injection site in some patients. Subjects receiving BNT162b1 also had higher levels of fever, fatigue, and chills compared to BNT162b2, and these were more common in older adults.
Pfizer and BioNTech have already enrolled more than 11,000 for the 30,000 subjects it plans to include in the ongoing 2/3 clinical trial for BNT162b2. The drugmakers hope to have enough data in October to begin looking for a regulatory check.
As regulators determine that BNT162b2 is safe and effective, Pfizer and BioNTech say they are ready to deliver up to 100 million doses by the end of this year – enough to vaccinate 50 million people – about 1.3 billion doses.
