New vaccine developments raise hopes even as virus variants proliferate

As coronavirus infections decline worldwide, a flood of good news on vaccine development is raising hopes of a potentially earlier end to the pandemic. A new, cheaper and simpler single-shot vaccine from Johnson & Johnson is on the verge of being approved in the United States, while U.S. drugmaker Moderna has said that it retooled its serum to confront spreading new variants.

Experts fear that there could be a new global wave of covid-19 powered by more transmissible variants of the virus, including those with the ability to evade vaccines. In addition to variants discovered in Brazil, Britain and South Africa, the United States has now reported its own more virulent variants in New York and California.

Scientists say that the key to preventing more variants from emerging is to stop the virus from circulating unrestricted around the world. An initial step is the arrival in Ghana this week of the first vaccine doses from the global Covax initiative to get injections to poorer nations.

Here are some significant developments:

The Food and Drug Administration has declared Johnson & Johnson’s new single-shot vaccine to be safe and effective, setting the stage for it to be authorized as soon as this weekend.

New unemployment claims decreased by 111,000 last week, the biggest drop in new claims since August, and a positive sign as the coronavirus pandemic spread has slowed in recent weeks.

More than 500,000 people have died of covid-19 in the United States, and more than 28 million cases have been reported. The past few weeks, however, have seen a steady decline in fatalities and rates of new cases.

Moderna said Wednesday that it has manufactured a new version of its coronavirus vaccine that is tailored to quell infection by the variant first identified in South Africa.

A new, more transmissible coronavirus variant detected in California this winter rapidly became dominant in the state over five months and now makes up more than half of the infections in 44 counties, according to new research.

Just hours after D.C. Mayor Muriel E. Bowser confirmed 1,000 covid-19 deaths in her city, she made another somber announcement, this one far more personal: Her sister had died of the virus.