‘We knew vaccines would not be a silver bullet’, says WHO on monkeypox

The vaccines available against monkeypox are safe, but there is a lack of data on the effectiveness of immunizations, said Rosamund Lewis, technical leader of the WHO (World Health Organization) on Wednesday (17).

“We knew from the beginning that vaccines would not be a silver bullet,” said the expert at a press conference organized by the entity. Even so, research already indicates some effectiveness in stopping the evolution of the disease, in addition to the importance of adopting other preventive measures.

Lewis explained that there are still no randomized clinical trials – the gold standard in scientific research – on the effectiveness of vaccines in the current outbreak. Even so, they can happen.

“We see that randomized control studies are feasible and we encourage countries to do so,” he said.

But there is already other evidence about the effectiveness of immunizations. According to Lewis, some observational investigations have reported the reduction of infection and severities in cases where the vaccine is applied in the post-prophylaxis regimen. In these cases, the vaccine is applied to a person who has had contact with someone infected in order to stop the progression of the disease.

The technical leader’s speech alerts mainly to the fact that it is recommended to adopt other prevention actions, in addition to vaccination, in the case of people who feel at greater risk of contracting the disease. One of them is to decrease the number of sexual partners, since most infections are occurring during sexual intercourse.

Outside of sex, other measures can also be taken, such as avoiding gatherings where skin-to-skin contact occurs and isolating suspected people with a confirmed diagnosis of monkeypox.

Lewis also recalled that, when taking the dose, it is important to wait at least two weeks for the immunizing agent to take effect.

Currently, the Jynneos vaccine, from the Danish pharmaceutical company Bavarian Nordic, is the only licensed immunizer in the world for monkeypox. It has already been approved for disease prevention by major international agencies such as the US Food and Drug Administration (FDA) and the European Commission.

Another possibility is the use of vaccines that were developed to prevent common smallpox. One such case is ACAM2000, which is being adopted against monkeypox in the United States.

For Brazil, 50,000 doses of the immunizing agent Jynneos are planned. 20,000 of them are expected to arrive in September and the rest in October.

Vaccines for other diseases have also not demonstrated 100% effectiveness in prevention. Covid-19 is an example: the available immunizations are effective to avoid serious conditions, but they do not prevent the virus infection.

Sylvie Brand, director of the area of ​​global preparedness for risks of infection, warned during the press conference that it is important to fight fake news and follow official and safe information, as in the case of vaccination against monkeypox.

“Maybe they can refuse a vaccine that can save their life”, exemplified Brand, citing cases of people who give up immunization because of fake news.

Currently, there are more than 35,000 confirmed cases of monkeypox in 92 countries. In Brazil, there have already been 3,184 confirmed diagnoses until this Tuesday (16), according to data from the Ministry of Health.

In addition to the cases, the WHO has already recorded 12 deaths from monkeypox worldwide.