Second Dose of J. & J. Vaccine Gives Strong Boost, Company Reports

A booster shot of the Johnson & Johnson vaccine increases antibody levels to the coronavirus dramatically, the company reported on Wednesday.

Johnson & Johnson will submit the data to the Food and Drug Administration, which is evaluating similar studies by Pfizer and Moderna. If approved by the agency, the Biden administration will give booster vaccinations eight months after vaccination.

The Johnson & Johnson vaccine was missing from the government’s original booster plan announced last week. With the new data, however, the company hopes to be part of the first distribution of additional footage, which could come as early as September.

“We look forward to discussing with public health officials a possible strategy for our Johnson & Johnson Covid-19 vaccine, which will be boosted eight months or more after the primary single-dose vaccination,” Dr. Mathai Mammen, global head of Janssen Research & Development at Johnson & Johnson, said in a statement.

In February, the FDA granted Johnson & Johnson an emergency approval for its single-use vaccine. A clinical study conducted last fall and winter showed that a single injection was 72 percent effective in preventing symptomatic Covid-19 in US participants. In the study, none of the vaccinated volunteers were hospitalized or died.

Johnson & Johnson conducted its clinical study before the Delta variant spread, leaving the question of how well the vaccine works against the highly contagious form of the virus. However, in a study published earlier this month, South African researchers found that a single shot of the Johnson & Johnson vaccine was up to 95 percent effective against death from the Delta variant and reduced the risk of hospitalization by 71 percent.

In its new study, Johnson & Johnson tracked 17 volunteers from last year’s clinical study. Six months after the vaccination, her antibody level had barely changed.

This differs from the pattern seen with the Moderna and Pfizer-BioNTech vaccines. These shots initially produce higher levels of antibodies, but their levels then drop over several months.

When volunteers in the Johnson & Johnson study received a booster dose after six months, their antibodies to the coronavirus rose nine times higher than after the first dose.

Studies of Moderna and Pfizer BioNTech vaccines found comparable increases in antibody levels. Since the three vaccines were not tested in a head-to-head comparison, it is not possible to determine which one provides the greatest boost.

Johnson & Johnson announced they have submitted a manuscript describing the research to the Medrxiv website. It hasn’t been posted there yet.


Aug 25, 2021, 10:00 a.m. ET

A number of studies suggest that higher antibody levels offer better protection, especially against the Delta variant. But other parts of the immune system such as T cells are also important. These data therefore cannot give an exact estimate of how effective the booster vaccination against Covid-19 will be.

“It is too early to assess the protection,” said Dr. Dan Barouch, a virologist at Beth Israel Deaconess Medical Center in Boston, who led some studies for Johnson & Johnson but was not involved in the booster study.

Aside from antibodies, Johnson & Johnson researchers also found that the booster increased the body’s supply of immune cells that can attack cells infected with the coronavirus. These results are still being prepared for publication.

The Johnson & Johnson vaccine uses an adenovirus to transport coronavirus genes into cells. When the company started its studies, some companies wondered if people were making antibodies to the adenoviruses that could render a booster useless. The new findings show that this is not the case.

“Something that we would have previously considered a big barrier may not be that big a barrier,” said Lynda Coughlan, a virologist at the University of Maryland School of Medicine who was not involved in the study.

The Johnson & Johnson vaccine is the only vaccine approved as a single dose in the United States or Europe. Since November, the company has been conducting a clinical study to investigate how much protection people get from two doses two months apart. This study should deliver results in the next few weeks.

After the volunteers in this study received the second dose, their antibody levels increased by a factor of three. The much larger increase in the new booster study is likely due to the longer wait between doses. The six-month hiatus gives the immune system time to develop a more mature response to the coronavirus.

This spring, Johnson & Johnson’s vaccine distribution in the United States was severely hampered by manufacturing mishandling by a contractor at a Maryland factory. Only eight percent of Americans vaccinated – or about 14 million people – have received a Johnson & Johnson vaccine, according to the Centers for Disease Control.

Since then, US supply of the vaccine has grown. A federal official said the government had sufficient reserves to provide boosters to anyone who received a first dose of Johnson & Johnson, should it be approved.

News of potential Johnson & Johnson boosters for Americans could sting other countries still waiting for their first doses of the vaccine. South Africa, for example, ordered 31 million doses of the vaccine, but only two million people there received it.

In an interview with CNBC last month, a Johnson & Johnson executive said the company plans to produce 500 to 600 million cans worldwide by 2021.

It remains to be seen how long the high levels of antibodies produced by the booster will last. “We don’t have long-term human studies, but my prediction would be that these responses should be sustained after the boost,” said Dr. Coughlan.

Noah Weiland contributed the reporting.

Comments are closed.