Johnson & Johnson’s COVID-19 vaccine showed promising signs in a small laboratory study of protecting against the Delta variant spreading across the U.S. and other countries, the company said.
In laboratory testing, the vaccine triggered strong levels of neutralizing antibodies in blood samples taken from eight vaccinated people, J&J said Thursday.
The positive performance adds to a growing set of evidence indicating currently authorized Covid-19 vaccines can safeguard against the Delta variant, which appears to be more contagious than earlier strains.
How well the J&J shot fares against the Delta variant has been closely watched by health authorities around the world.
Many countries have been counting on supplies, especially because the vaccine is simpler to ship, handle and store than the shots from Pfizer Inc. and its partner BioNTech SE and from Moderna Inc.
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The new findings "reinforce the ability of the Johnson & Johnson COVID-19 vaccine to help protect the health of people globally," said J&J Chief Scientific Officer Paul Stoffels.
J&J also said its vaccine provides protection against COVID-19 for at least eight months, the most time that researchers were able to study the shot’s durability.
The Delta variant first emerged in India late last year. Since then, it has spread rapidly, becoming the most common strain of the COVID-19 virus in several countries, including the U.S.
The variant made up about 40% of positive COVID-19 test samples as of June 27, according to population genomics company Helix OpCo LLC, which collects and analyzes test samples from several U.S. states.
Vaccination is the best defense against the Delta variant, according to public-health authorities, who have cited the threat posed by the strain in urging people to get immunized.
So far, studies have indicated various vaccines appear effective against the Delta strain, especially once individuals have been fully vaccinated, though the shots aren’t as protective as they are against the original virus.
Separate studies in England and Scotland found that vaccines from Pfizer-BioNTech and AstraZeneca PLC offered substantial protection from the Delta variant against severe cases of Covid-19 and hospitalization.
England’s public health agency said an analysis of 14,000 cases found the Pfizer-BioNTech shot reduced the risk of hospitalization after infection with Delta by 96%.
J&J’s single-dose shot is based on a different technology than the Pfizer-BioNTech and Moderna vaccines, but operates similar to AstraZeneca’s.
J&J’s shot uses a modified version of the virus responsible for the common cold, to carry genetic instructions teaching cells how to make the spike protein that juts from the surface of the coronavirus.
Production of the spike protein, in turn, prompts the immune system to develop molecular defenses against the coronavirus.
In its large, pivotal study, the J&J vaccine was 66% effective in protecting against severe disease, though it appeared to be less effective against the variant first found in South Africa, now called Beta.
Overall, however, it was highly effective in places where variants were spreading during the trial. The U.S. Food and Drug Administration authorized the shot in February.
J&J said the neutralizing-antibody activity found in its recent laboratory study was higher for the Delta variant than for Beta.