Johnson & Johnson Says Second Shot Boosts Protection to 94%

Carolyn Crist

September 21, 2021

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Johnson & Johnson announced Tuesday that a second shot of its vaccine boosts efficacy to 94% against moderate and severe COVID-19.

When given two months after the first dose, a booster shot increased antibody levels by four to six times compared with one shot alone. When given six months after the first dose, a booster shot increased antibody levels 12-fold.

"Our single-shot vaccine generates strong immune responses and long-lasting immune memory," Mathai Mammen, MD, global head of Janssen Research and Development at Johnson & Johnson, said in a statement.

"And, when a booster of the Johnson & Johnson COVID-19 vaccine is given, the strength of protection against COVID-19 further increases," he said.

The 94% efficacy rate was observed in the U.S., the company said. Globally, a booster shot given two months after the first dose was 75% effective.

Earlier this year, Johnson & Johnson said that its single-shot vaccine is 66% effective in preventing moderate COVID-19 and 85% effective against severe disease, according to CBS News.

According to the latest study data, a second shot led to an increase in antibodies for all ages. The side effects were similar to the ones seen after the initial dose.

The company said it provided data to the FDA and plans to submit data to other regulators worldwide to seek approval for booster doses. Nearly 15 million Americans have received the single-dose vaccine, according to CNBC.

Tuesday's announcement came as U.S. officials continue to discuss booster shots as a potential avenue to halt the contagious Delta variant. More than 675,000 Americans have died from COVID-19, which is equivalent to the number of deaths reported during the 1918-1919 Spanish flu pandemic.

An independent FDA advisory panel has recommended a third dose of the Pfizer vaccine for ages 65 and older and high-risk adults at six months following the second dose. The FDA is expected to make a final decision in coming days, CNBC reported.

"It is critical to prioritize protecting as many people as possible against hospitalization and death given the continued spread of COVID-19," Paul Stoffels, MD, chief scientific officer at Johnson & Johnson, said in the statement.

"A single-shot COVID-19 vaccine that is easy to use, distribute and administer, and that provides strong and long-lasting protection, is crucial to vaccinating the global population," he said. "At the same time, we now have generated evidence that a booster shot further increases protection against COVID-19 and is expected to extend the duration of protection significantly."


Johnson & Johnson: "Johnson & Johnson Announces Real-World Evidence and Phase 3 Data Confirming Strong and Long-Lasting Protection of Single-Shot COVID-19 Vaccine in the U.S."

CBS News: "Johnson & Johnson says study shows two doses of its vaccine offer 94% protection against COVID-19."

CNBC: "J&J says Covid booster shot is 94% effective in the U.S. when given two months after first dose."


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