Single dose of Jynneos vax 78% effective against mpox: Lancet

London, March 15

A single dose of the Jynneos vaccine is 78 per cent effective against symptomatic mpox infection, according to a study published in The Lancet Infectious Diseases.

Mpox (formerly known as monkeypox) is caused by a virus that is related to the virus that causes smallpox.

Jynneos, is a Modified Vaccinia Ankara (MVA)-based live, non-replicating and two-dose vaccine, that was approved for monkeypox prevention for adults at high risk of mpox infection.

People need to get both doses of the vaccine for the best protection against mpox. The second dose should be given 4 weeks after the first dose.

But the study showed that the estimated one-dose vaccine efficacy against symptomatic mpox was 78 per cent after at least 14 days.

"A single MVA-BN (Jynneos) dose was highly protective against symptomatic mpox disease among at-risk (MSM), making it a useful tool for mpox outbreak control when rapid protection is needed," wrote the researchers including Jamie Lopez Bernal, Immunizations and Vaccine Preventable Diseases Division, UK Health Security Agency.

"For cases in which numbers at highest risk of infection exceed vaccine supply, there might be benefit in prioritizing delivery of first doses."

Mpox is a viral zoonotic disease that occurs primarily in tropical rainforest areas of central and west Africa and is occasionally exported to other regions.

As many as 85,765 confirmed and 1,382 probable cases of mpox (monkeypox) were reported from 110 countries since January 1, 2022, the World Health Organization (WHO) said last month.

--IANS