Johnson & Johnson: Booster dose of its COVID shot prompts strong response

A close-up look at gloved hands loading a syringe with a dose of the Johnson & Johnson COVID-19 vaccine
Johnson & Johnson says that a booster of its vaccine — given either two months or six months after the initial shot — increases protection.
(Matt Rourke / Associated Press)

Johnson & Johnson said Tuesday that a booster of its one-shot COVID-19 vaccine provides a stronger immune response months after people receive a first dose.

J&J said in statement that an extra dose — given either two months or six months after the initial shot — revved up protection. The results haven’t yet been published or vetted by other scientists.

The J&J vaccine was considered an important tool in fighting the pandemic because it requires only one shot. But even as rollout began in the U.S. and elsewhere, the company already was running a global test of whether a two-dose course might be more effective — the second dose given 56 days after the first.


That two-dose approach was 75% effective globally at preventing moderate to severe COVID-19, and 95% effective in the U.S. alone, the company reported — a difference probably due to which variants were circulating in different countries during the months-long study.

Examined a different way, the company said when people got a second J&J shot two months after the first, their levels of virus-fighting antibodies were four to six times higher. But giving a booster dose six months after the first J&J shot yielded a twelvefold increase.

A second dose of the Johnson & Johnson vaccine led to an increase in COVID-19-fighting antibodies, the company said.

Aug. 25, 2021

While the single-dose vaccine remains effective, “a booster shot further increases protection against COVID-19 and is expected to extend the duration of protection significantly,” Dr. Paul Stoffels, J&J’s chief scientific officer, said in a statement.

The company previously published data showing its one-shot dose provided protection for up to eight months after immunization. It also pointed to recent real-world data showing 79% protection against coronavirus infection and 81% protection against COVID-19 hospitalization in the U.S. even as the extra-contagious Delta variant began spreading.

J&J said it has provided the data to regulators, including the U.S. Food and Drug Administration, the European Medicines Agency and others, to inform decisions about boosters.

The company’s vaccine is approved for use in the U.S. and across Europe, and there are plans for at least 200 million doses to be shared with the United Nations-backed COVAX effort aimed at distributing vaccines to poor countries. But J&J has been beset by production problems, and millions of doses made at a troubled factory in Baltimore had to be thrown out.


As the Delta variant spread worldwide, numerous governments have considered the use of booster shots for many of the COVID-19 vaccination options.

The panel approves a COVID booster shot plan for high-risk Americans after rejecting a more sweeping proposal.

Sept. 17, 2021

Last week, advisors to the FDA recommended people 65 and older get a third dose of the COVID-19 vaccine made by Pfizer and German partner BioNTech. A final decision is pending.

Britain previously authorized booster shots for people 50 and older and to priority groups such as health workers and those with other health conditions. Countries including Israel, France and Germany have also begun offering third vaccine doses to some people.

The World Health Organization has urged rich countries to stop giving booster doses until at least the end of the year, saying vaccines should immediately be redirected to Africa, where fewer than 4% of the population is fully vaccinated.

Last week in the journal Lancet, top scientists from the WHO and FDA argued that the average person doesn’t need a booster shot and that the authorized vaccines to date provide strong protection against severe COVID-19, hospitalization and death.