All you need to know about Johnson & Johnson's Covid-19 vaccine

J&J vaccine was 66% effective in preventing moderate-to-severe Covid-19 globally

Johnson & Johnson’s single-dose Covid-19 vaccine was given approval for emergency use in India on Saturday.

Here's what you need to know about J&J's shot.

How effective was it in a large study?

Results from a trial of about 44,000 participants show the J&J vaccine was 66 per cent effective in preventing moderate-to-severe Covid-19 globally.

A review of available data by an independent safety monitoring board indicated that a single-dose of the Covid-19 vaccine was generally well-tolerated.

Demographics

About 34 per cent of trial participants were over age 60.

17.2 per cent of participants in the trial were Black, 8.3 per cent were American Indian or Alaskan Native, 2.5 per cent were Asian and 45 per cent were Hispanic or Latino.

Side effects

The US FDA said the most common reactions were injection site pain at 48.6 per cent, headache at 39 per cent, fatigue at 38.2 per cent and aches and pains at 33.2 per cent. Other side effects included a fever in 9 per cent of participants and a high fever in 0.2 per cent of those who received the vaccine.

How does it differ from the Pfizer and Moderna vaccines?

The Pfizer/BioNTech and Moderna vaccines use new messenger RNA technology to create an immune response and both require two shots. The one-shot J&J vaccine involves a more conventional approach, using a common cold virus to introduce coronavirus proteins into cells to trigger an immune response.

Also read: Johnson and Johnson's single-dose Covid-19 vaccine approved for emergency use in India

J&J's vaccine remains stable for at least three months at normal refrigerator temperatures, while the Moderna vaccine must be shipped frozen and the Pfizer/BioNTech option must be shipped and stored at even colder sub-Arctic temperatures.

These factors make it easier to vaccinate larger numbers of people, even in areas with poor transportation and storage infrastructure.

Pfizer/BioNTech and Moderna vaccines were about 94 per cent-95 per cent effective in trials conducted in the United States where variants were not circulating.

How does it rank next to the others?

Both mRNA vaccines showed higher efficacy rates in their trials than J&J's vaccine, but experts cautioned against drawing too much of a distinction between the vaccines because the trials had different endpoints and J&J's was conducted while highly transmissible new variants of the virus were circulating.

Novavax Inc, which is testing its vaccine in South Africa, said it was 60 per cent effective at preventing mild, moderate and severe Covid-19 in patients who did not have HIV. It said about 90 per cent of cases in the study involved the new South African variant. The mid-stage South Africa trial included 4,400 patients.

The vaccine developed by AstraZeneca with Oxford University provided only minimal protection against mild-to-moderate Covid-19 from the South African variant in a relatively small trial. There was no data yet on its effectiveness in preventing severe disease in people who were infected by the variant because the study involved mostly young adults not considered to be at high risk for serious illness.

(With Reuters inputs)