“It’s possible for asymptomatic cases to exist — which I think are fewer in this pathology — but the possibility of transmission from asymptomatic individuals is still not well understood,” explains Ana Abecasis, assistant professor at the Institute of Hygiene and Tropical Medicine (IHMT) of the Universidade Nova de Lisboa.
The most recent Mpox outbreak, previously called ‘monkeypox’, is caused by ‘clade I’ from Central Africa, which is different from the one that caused the 2022 outbreak with several cases in Europe, ‘clade II’ from East Africa.
“These clades have different characteristics in terms of symptoms,” she says. “Clade II caused less frequent and more localized skin eruptions, while clade I has more dispersed eruptions throughout the body, which makes its symptoms more severe. However, symptoms such as fever, headaches, and lymphadenopathy [a condition where lymph nodes have abnormal size, consistency, or number] are common in both,” she states.
Apparently, the most recent strain is more violent, although the researcher emphasized that she has not yet found “clear information regarding the mortality rate.”
“What is described is that this strain has higher mortality rates, with the information I found stating that it has a percentage of 1 to 10%, while clade II had 2 to 6%, but this also depends on the affected areas,” she highlights.
Ana Abecasis explains that the mortality rate between strains should not be directly compared, as the 2022 outbreak had cases in Europe, which has a greater response capacity, and the current outbreak is mainly affecting Africa, where there is a lack of infrastructure and health professionals.
Clade I is more frequently transmitted from human to human, which facilitates its spread. On Thursday, the first case in Europe was announced in Sweden, so “there is a high need for prevention,” she emphasizes.
Specifically about Africa, “the best response (…) to address this outbreak is through prevention because, in terms of response capacity of human resources in health for treatments, we know that we have limited resources in these contexts and it ends up being more difficult to act,” she laments.
Therefore, prioritizing vaccination “will be the best strategy to try to overcome this lack of human resources,” she advises.
The World Health Organization (WHO) has a series of recommendations, ranging from early diagnosis, case isolation, partner notification, contact identification, and vaccination, but the number of available vaccines is still low, she says.
Currently, there is the issue of vaccine production, distribution, and prioritization of high-risk individuals to start being vaccinated, but the local context can complicate this action.
However, the GAVI Vaccine Alliance, whose president is Durão Barroso, former Portuguese prime minister, has a response plan with a financial allocation for this type of emergency of 500 million dollars (about 455 million euros) and announced on Friday the creation of a global reserve of vaccines against Mpox.
“In this case, we will have to ensure that these vaccines are distributed in a coordinated manner and that local entities can control the cases that arise and identify contacts, in order to prevent the epidemic from spreading rapidly,” says the researcher.
The professor considers it crucial to define high-risk groups.
“I haven’t seen anything defining high-risk groups in this case yet. We know that there are many infections in children, that there is vertical transmission, and in this case, the mortality rate is higher,” she emphasizes.
Since the previous outbreak in 2022, there has been a research and preparation response for smallpox, she indicates.
Regarding Portugal, “there needs to be awareness among health professionals about the symptomatology of this disease, or the spectrum of symptoms, with a view to the possible existence of imported cases, so that we can act immediately to isolate them,” she says.
“I also don’t know what is planned in terms of controlling the entry of people from these most affected regions, but it’s important to do some surveillance, which would be an effective strategy,” she advises.
However, she emphasized that there must be resource management and an understanding of the extent to which mass testing can be done at borders.
In Portugal, there are already about 17,000 vaccinated people, who were in the high-risk group from the 2022 outbreak, she specifies.
The researcher also emphasizes that, in her opinion, “all available vaccines should be channeled to the countries that are facing outbreaks at the moment,
