Johnson & Johnson's COVID-19 vaccine, which has the advantage of a single vaccination, has been evaluated as not as expected, revealing 66% of the preventive effect.

Experts are suggesting that approval is expected as long as they exceed the minimum standards of the WHO, but the evidence should be supplemented.

On the 29th, Johnson & Johnson released the results of clinical trials for its vaccine (Janssen vaccine) at local time. Clinical results show that this vaccine has an average of 66% prophylactic effect (72% in the US, 66% in Latin America, and 57% in South Africa).

These results are relatively low compared to Pfizer 95%, Moderna 94.1%, and Novavax 89.3%, which is not good even considering the strength of single dose. This is same as when there was an announcement that AstraZeneca's COVID-19 vaccine had a prophylactic effect of about 62%.

However, experts explain that the Janssen vaccine can be approved based on the efficacy criteria of the vaccine published by the WHO.

Choi Won-seok, a professor of infectious medicine at Korea University Anam Hospital, said, "When COVID-19 vaccine was first developed, the criterion that we thought we could respond to the epidemic was about 50% of the prevention effect. All the vaccines available so far, including Janssen, have exceeded this standard."

He said, "The standard for responding to COVID-19 epidemic is 70%. Janssen recorded an average of 66%, but in the US clinical trials, the result was more than 70%, so it will meet the US Food and Drug Administration (FDA) standards."

Johnson & Johnson plans to apply for Emergency Use Authorization from the Food and Drug Administration (FDA) as early as this week, and a preliminary review has been requested in Korea.

In this regard, Kang Jin-han, director of the Vaccine Bio Research Institute at Catholic University of Medicine, said, "It is said that if the vaccine prevention effect is more than 50%, it is normal and it is good if it is more than 70%. if the prevention effect is more than 50%, it will be approved."

However, he said that while evaluating that a single dose of Janssen vaccine is meaningful, it is also clear that the preventive effect is lower than expected.

He said, "The data aren't all public and can't be concluded. The evidence is not clear on how long a single dose lasts independent of the seroconversion rate. It should be said that the preventive effect should be sustained like the two doses, but it is unfortunate that this part is not clear."


The Janssen vaccine is a single vaccination and is easy to distribute and store. Who is vaccinated?

In addition to the single vaccination, the Janssen vaccine has the advantage of being easy to set up an inoculation plan because it remains effective for more than 3 months in refrigerated distribution and storage, and is delivered in a 5-dose vial package that does not require dilution.

The vaccine for 6 million people will be supplied from the second quarter, and Johnson & Johnson is confident that there will be no disruption in the contracted supply. Experts believe that it is effective to first inoculate the elderly living in the facility.

Professor Wonseok Choi said, "It is difficult to judge a specific profile before knowing it, so we should prioritize storage and accessibility. However, if there is a limited supply and there is no option of a vaccine, we have no choice but to inoculate at the currently selected priority." He stressed, "If the characteristics of each vaccine are similar and do not have a significant effect, we will have to prioritize vaccination, which shows clinically more effective."