New data from Johnson & Johnson shows second shot boosts antibodies and protection against COVID-19 – but one dose is still strong against the delta variant

On September 22, 2021, Johnson & Johnson released data that answers two questions many people have probably asked about their vaccine: How effective is it against the delta variant and do I need a booster? Maureen Ferran, a virologist at the Rochester Institute of Technology, kept tabs on the Johnson & Johnson vaccine. She breaks down the new data and explains what it all means.

1. How effective is a dose of Johnson & Johnson vaccine?

The first clinical trial data published in January 2021 showed that four weeks after the first dose, Johnson & Johnson’s single-injection vaccine was 66.3% effective in preventing COVID-19 infection. Early studies also showed it to be 85% effective in preventing serious or critical illnesses.

But the original clinical trials and most subsequent studies were done before the delta variant became responsible for nearly all COVID-19 cases in the United States Early studies suggest that although COVID-19 vaccines are still effective against this variant, in general their effectiveness is lower compared to the protection against the original strain.

On September 21, 2021, Johnson and Johnson announced the results of a large, real-world Phase 3 clinical trial of their COVID-19 vaccine. This study collected data from March 1, 2020 to July 31, 2021 and found that the vaccine’s efficacy did not decrease over the duration of the study, even after the delta variant became dominant in the United States. United. The single-dose vaccine was 79% protection against COVID-19 infections and 81% protection against COVID-19-related hospitalizations. This indicates that a single Johnson & Johnson shot works well, even in the presence of the Delta and other variants.

2. Why might someone need a reminder?

The amount of neutralizing antibodies in a person – antibodies that defend a cell against the coronavirus – is an accurate measure of protection in the first few months after vaccination. Studies show that people who have received a Johnson & Johnson vaccine or an mRNA vaccine continue to produce a certain level of antibodies for at least six months after vaccination. However, the levels of neutralizing antibodies usually begin to decline over time and some evidence suggests that the immunity provided by Pfizer mRNA vaccine does the same.

The story continues

It may sound bad, but it’s not clear whether lower antibody levels correlate with an increased risk of serious infection. Long-term monitoring of the immune system is done by “memory” immune cells that will prevent or reduce the severity of illness if a person is exposed to the coronavirus at a later time.

Therefore, scientists collected real data from vaccinated people to determine when they might become vulnerable to infection again with and without a booster injection.

3. How effective is a Johnson & Johnson booster injection?

In addition to the results of the single injection study, on September 21, 2021, Johnson & Johnson also released data on booster injections. The trial gave people a second dose of the Johnson & Johnson vaccine two to six months after the first dose. In both cases, it has increased people’s defense against COVID-19.

When given two months after the first dose, protection against moderate to severe disease increased from 85% to 94% and the amount of neutralizing antibodies quadrupled. If the booster was given six months after the first injection, the antibody levels increased 12-fold when measured four weeks after the booster was given.

These results suggest that although a single dose of the Johnson & Johnson vaccine provides strong and long-lasting protection, people may still benefit from a booster because it improves the effectiveness of the vaccine.

An important question is whether a person who has received the Johnson & Johnson vaccine should get a second Johnson & Johnson dose or mix and match – get a second dose of a different vaccine. At the end of September, the FDA seems more likely to approve a second dose of the Johnson & Johnson vaccine because there isn’t much data on a mix-and-match strategy yet.

4. What about side effects?

The vast majority of vaccines – including the Johnson & Johnson and COVID-19 mRNA vaccines – produce common side effects, such as pain at the injection site, headache, fatigue, muscle and joint pain, chills and fever.

The recent study did not monitor the side effects of the booster in detail, but according to Johnson & Johnson, the safety of the vaccine has remained consistent and was generally well tolerated when given as a booster. Overall, researchers have repeatedly found that despite some rare complications, the benefits of the Johnson & Johnson vaccine far outweigh the risks.

A recent CDC study showed that unvaccinated people are nearly five times more likely to be infected with the coronavirus and 29 times more likely to be hospitalized with COVID-19 compared to fully vaccinated people. Therefore, all the evidence suggests that the millions of Americans who can get the vaccine but choose not to do so are putting themselves – and others – at risk.

5. When can a recall be authorized?

On September 22, 2021, the FDA approved booster shots for people who received the Pfizer vaccine and aged 65 and over, at risk of serious illness from COVID-19 or whose occupations put them at greater risk of illness. ‘exposure. Booster shots for the Johnson & Johnson or Moderna vaccines are not yet approved, but on September 19, Dr Anthony Fauci said the FDA may review the booster data for the Moderna and Johnson & Johnson vaccines within weeks. .

Parts of this article were originally published in a previous article originally published on August 27, 2021.

[Over 110,000 readers rely on The Conversation’s newsletter to understand the world. Sign up today.]

This article is republished from The Conversation, a nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Maureen Ferran, Rochester Institute of Technology.

Read more:

Maureen Ferran does not work, consult, own stock or receive funding from any company or organization that would benefit from this article, and has not disclosed any relevant affiliation beyond her academic position.