Moderna's Covid vax more effective against Delta than Pfizer, J&J: Study

Moderna's vaccine for Covid-19 is significantly more effective against the Delta variant of the SARS-CoV2 virus than Pfizer or Johnson & Johnson, suggests a new study.

The study, published in Morbidity and Mortality Weekly Report, suggests that Moderna was 95 per cent effective at preventing hospitalisation among adults ages 18 and older.

"These real-world data show that vaccines remain highly effective at reducing Covid-19 related hospitalisation and emergency department visits, even in the presence of the new Covid-19 variant," said researcher Shaun Grannis from Indiana University in the US.

"We strongly recommend vaccinations for all who are eligible to reduce serious illness and ease the burden on our healthcare system," Grannis added.

The team also found that Pfizer was 80 per cent effective at preventing hospitalisation among adults ages 18 and older. While Johnson & Johnson was 60 per cent effective.

For the study, the team analysed more than 32,000 medical encounters from nine states during June, July and August 2021, when the Delta variant became the predominant strain.

The results showed that unvaccinated individuals with Covid-19 are 5-7 times more likely to need emergency department care or hospitalisation, similar to the overall effectiveness prior to the variant.

The study also found that vaccine effectiveness is lower for people 75 years and older, which has not been shown in previous research.

This could be due to a range of factors, including the increased time since vaccination, the researchers noted.