What Will it Take to Make Covid-19 Vaccines Variant-Proof?
Last week, two more pharmaceutical firms backed by the US federal government’s Operation Warp Speed program announced preliminary results from large-scale clinical trials of their Covid-19 vaccines. And both had very welcome results to report. Mostly.
According to Johnson & Johnson’s press release, the company’s single shot was 85 percent effective in preventing severe forms of the disease across the 44,000 people enrolled in each of three trials in the United States, Latin America, and South Africa. But when it came to fending off more mild cases of coronavirus infection, the vaccine worked best in the US, where it was 72 percent protective compared to just 57 percent in South Africa. (The shot’s efficacy in Latin America was 66 percent.)
It was the same story with Novavax, a much smaller, Maryland-based company. In its 15,000-person United Kingdom trial, the vaccine demonstrated 89 percent efficacy against mild, moderate, and severe cases of Covid-19; in the company’s smaller study in South Africa, the efficacy rate fell to about 50 percent.
