Monkeypox epidemic: new challenges, new strategies

Following the latest outbreak of mpox, more than 86,000 people were infected worldwide and the possibility of mpox becoming endemic outside its original geographic area suddenly became plausible. If so, its presence would lead to repeated infections in humans and/or continued human-to-human transmission.

In northern countries, it is men who have sex who have been most exposed to this new disease and their mobilization, as well as isolation measures, contact tracing and access to a more effective vaccine than expected, has seen the numbers improve and the threat recede, but isolated cases continue to be reported in 28 countries as of March 2023.

The possibility of continuous or epidemic transmission, particularly in summer, raises concerns about the evolution of the virus—in terms of transmissibility and pathogenicity—and its expansion beyond current exposed groups.

Mpox in Europe

As of 10 April 2023, 25,874 confirmed cases of monkeypox (mpox), including six deaths, have been reported from 45 countries and territories in the WHO European Region. Of these cases reported in TESSy, 25,584 were laboratory confirmed. When sequencing was available, 489 were confirmed to belong to cluster II (formerly West Africa).

The number of weekly cases reported in Europe has now fallen by more than 95% from the highest levels in late summer 2022. Nevertheless, low-level autochthonous transmission persists in several European countries, with a total of 28 cases reported in seven countries in the previous four weeks (still as of April 10).

The largest proportion of cases is between 31 and 40 years old (10,146 out of 25,731, or 39%) and the vast majority are men (25,268 out of 25,713, 98%). Of the 11,394 male cases with known sexual orientation, 96% said they were men who have sex with men. Among the cases whose serological status HIV Human immunodeficiency virus. In English: HIV (Human Immunodeficiency Virus). Isolated in 1983 at the Pasteur Institute in Paris; recently discovered (2008) rewarded with the Nobel Prize in Medicine awarded to Luc Montagnier and Françoise Barré-Sinoussi. was known, 38% (4,042 out of 10,623) were living with HIV. Majority of cases had rash (15,303 of 16,021, 96%) and systemic symptoms such as fever, fatigue, muscle aches, chills, or headache (10,855 of 16,021, 68%) . There were 783 hospitalized cases (6%), of which 271 required clinical care. Eight people were admitted to the intensive care unit and six cases of MPOX were reported as deceased.

How to deal with this epidemic outbreak, which seems to be continuing (see box below) and the challenges it poses to health systems?

A strategy in the face of these new outbreaks

In the field of public health, there are different strategies to deal with infectious diseases: control, elimination of transmission, elimination as a public health problem and eradication.

• Control is the reduction of incidence, prevalence Number of people affected by a given infection or other disease in a given population.morbidity and/or mortality of a disease at an acceptable level, at a local level.
• Elimination of transmission means the reduction to zero of the incidence of infection caused by a specific pathogen in a defined geographical area, with minimal risk of reintroduction. This is the aim of global programs concerning, among others, human African trypanosomiasis (sleeping sickness), leprosy and onchocerciasis (river blindness).
• Elimination as a public health problem (EPHP) corresponds to the reduction of the impact of a disease to a level where it is no longer considered a major public health problem. More than 30 diseases are concerned through global programs, including HIV, tuberculosis, malaria and viral hepatitis.
• Eradication refers to the permanent reduction to zero of the global incidence of a disease.

Regarding mpox, recent outbreaks have highlighted sustained transmission, from person to person, without animal contribution, but not on the whole planet. Faced with what was considered until now to be a zoonosis, the WHO proposes to change strategy and considers that the elimination of human-to-human transmission of mpox must be an objective.

To do so, the WHO intends to establish agreed global definitions and objectives, applicable in different countries and contexts. These strategies may in particular combine:

• Enhanced surveillance and early detection of cases;
• Decentralized testing capabilities and the development of rapid tests;
• Risk communication and community engagement;
• Vaccination of exposed populations, whether through human-to-human transmission, occupational risk for health professionals, exposure to infected animals or individuals living in enzootic/endemic areas;
• Isolation of infected persons and contact tracing;
• Infection prevention and control measures to minimize the risk of transmission in healthcare settings;
• Reduction of risk to others through good clinical case management.

Priorities for action

The authors of an American study, affiliated with the Global Virus Network, consider this epidemic to be a warning: pandemic preparedness plans require additional coordination and resources.

The study details several priorities for action, to learn from this outbreak episode:

1. Collect more data on the efficacy of vaccines (duration of the vaccine response for example; comparative efficacy of one dose versus two doses, impact of old vaccination with smallpox before 1979, etc.) and drugs in infected humans (Tecovirimat, immunoglobulins etc.);
2. Develop global collaborations to ensure that government authorities work with the private sector in developed and low- and middle-income countries to deliver treatments and vaccines, especially in historically endemic/enzootic areas;
3. Strengthen diagnostic and surveillance capacities to identify areas and populations where the virus is present and likely to cause a resurgence;
4. Inform people at high risk of serious complications—immunocompromised people, untreated HIV-positive people, pregnant women—, who must know the risk of infection and protect themselves against transmission of mpox;
5. Increase understanding and acceptance of public health measures through engagement with the communities most affected, and this in a non-stigmatizing way;
6. Establish repositories of clinical mpox samples, including blood, fluids, tissues and lesion specimens, for the research community.

As with all epidemics, the response will be as much political as health. Let’s hope that the governments will be able to take the first lessons of this episode and put in place these coordinated strategies.