At first glance, the results reported on Friday from the long-awaited trial of Johnson & Johnson s Covid-19 vaccine might have seemed disappointing. Its overall efficacy - the ability to prevent moderate and severe disease - was reported at 72 percent in the United States, 66 percent in Latin American countries and 57 percent in South Africa.
Those figures appear far below the high bar set by Pfizer-BioNTech and Moderna, the first two vaccines authorized for emergency use in the United States, which reported overall efficacy from 94 to 95 percent.
But Dr. Anthony S. Fauci, the nation s leading infectious disease expert, said that the more crucial measure was the ability to prevent severe disease, which translates to keeping people out of the hospital and preventing deaths. And that result, for Johnson & Johnson, was 85 percent in all of the countries where it was tested, including South Africa, where a rapidly spreading variant of the virus had shown some ability to elude vaccines.
Among the 100 million people around the world who have battled coronavirus infections, scientists are turning to the case of a 45-year-old COVID-19 patient in Boston to understand how the virus is able to outwit humans.
During his 154-day illness one of the longest on record the patient’s body became a crucible of riotous viral mutation. He offered the world one of the first sightings of a key mutation in the virus’ spike protein that set off alarm bells when it was later found in strains in the United Kingdom, South Africa and Brazil.
In the U.K. strain, the genetic change known as N501Y is thought to help enhance the virus’ transmissibility by about 50%. In the South Africa strain, it may reduce the effectiveness of COVID-19 vaccines and treatments. Tests of its effect on the Brazil variant are still in progress.