By Julie Steenhuysen

CHICAGO (Reuters) – Johnson & Johnson (NYSE:) said Tuesday a second shot of its COVID-19 vaccine given about two months after the first increased its effectiveness to 94% in the United States against moderate to severe forms of the disease.

This is 70% protection from a single shot.

The data will help J&J make its case to U.S. regulators for a booster shot even as the company stresses the durability of its single-shot vaccine as a tool to ease the global pandemic.

President Joe Biden is pushing for booster shots in the face of surging hospitalizations caused by the Delta variant and J&J, the only drugmaker with a single-shot COVID-19 vaccine approved in the United States, has been under pressure to produce evidence on the effectiveness of an additional dose.

The company has now “generated evidence that a booster shot further increases protection against COVID-19,” Dr. Paul Stoffels, J&J’s chief scientific officer, said in a statement.

J&J said a booster given two months after the first dose increased antibody levels four to six-fold. Data released last month revealed that antibody levels rose twelvefold six months after receiving the second dose. This suggests that there is a significant improvement in protection due to the longer time between the doses.

Studies with two doses of vaccine showed similar side effects to single-dose ones. While the data are still being peer-reviewed, they will be submitted to publication within the next few months.

To date, only Pfizer (NYSE:) Inc/BioNTech SE have submitted sufficient data for U.S. regulators to evaluate whether boosters are warranted ahead of the Biden Administration’s Sept. 20 deadline for rolling out booster shots. A decision on that vaccine https://www.reuters.com/article/us-health-coronavirus-usa-boosters-pfize/regulators-could-ok-pfizer-boosters-for-older-americans-this-week-idUSKBN2GG0KQ is expected this week.

An FDA advisory committee recommended Friday that additional Pfizer shots be authorized for Americans aged 65 or older, and people at higher risk of severe illnesses. But, the group voted not to approve a wider approval. They want more data.

J&J said it has submitted data to the FDA and plans to submit it to other regulators, the World Health Organization and other vaccine advisory groups worldwide to inform their decision-making.

A Phase III trial with up to 30,000. Participants tested whether a second dose of J&J vaccine could be effective 56 days later.

While the study found that two doses of the J&J vaccine was 94% effective in the United States at preventing moderate to severe disease, there was only 1 case in the vaccine group and 14 in the placebo group, resulting in a wide confidence interval and raising questions about the certainty of the result.

According to the company, after a 36-day follow up, they found that the second dose of J&J vaccine was tolerated well.

The company also said on Tuesday that evidence from a separate real world study of nearly 400,000 people in the United States who got the J&J shot showed the vaccine was 79% effective at preventing COVID-19 infections and 81% effective at preventing hospitalizations compared with 1.52 million people of similar ages, genders and health issues who were unvaccinated.

J&J said there was no evidence of reduced effectiveness over the study’s duration from March to late July – a period that included the impact of the Delta variant.

The age of the vaccine’s effectiveness was a factor in how effective it was in real-world studies. The vaccine prevented hospitalizations for people under 60 years of age by being 86% effective compared to 78% in the case of those over 60.