- NYTimes, Global Health, Dec. 19, 2021 -
- snip - A growing body of preliminary research suggests the Covid vaccines used in most of the world offer almost no defense against becoming infected by the highly contagious Omicron variant.

All vaccines still seem to provide a significant degree of protection against serious illness from Omicron, which is the most crucial goal. But only the Pfizer and Moderna shots, when reinforced by a booster, appear to have initial success at stopping infections, and these vaccines are unavailable in most of the world.

The other shots — including those from AstraZeneca, Johnson & Johnson and vaccines manufactured in China and Russia — do little to nothing to stop the spread of Omicron, early research shows. And because most countries have built their inoculation programs around these vaccines, the gap could have a profound impact on the course of the pandemic.

The disparity in the ability of countries to weather the pandemic will almost certainly deepen. And the news about limited vaccine efficacy against Omicron infection could depress demand for vaccination throughout the developing world, where many people are already hesitant or preoccupied with other health problems.

Antibodies are the first line of defense induced by vaccines. But the shots also stimulate the growth of T cells, and preliminary studies suggest that these T cells still recognize the Omicron variant, which is important in preventing severe disease.
“What you lose first is protection against asymptomatic mild infection, what you retain much better is protection against severe disease and death,” said John Moore, a virologist at Weill Cornell Medicine in New York. He called it “a silver lining” that Omicron so far appears less lethal than the Delta variant.