Monkeypox global health emergency: Everything you need to know

The World Health Organization (WHO) on Wednesday declared monkeypox (renamed mpox) a Public Health Emergency of International Concern (PHEIC), its highest alert level. A variant of the virus that causes it is spreading across Africa, apparently with greater transmissibility and lethality than the one that caused the 2022 outbreak. Here’s what’s known about the virus and the action the WHO has taken.

How is the virus spreading?

The outbreak is occurring in Africa, where 15,000 cases and 461 deaths from mpox have been recorded so far this year. The number of detected infections is much higher (160%) than last year at this time and is most likely only a small fraction of those that have actually occurred. Most of these cases are concentrated in the Democratic Republic of Congo, although the virus is already spreading to other countries such as Uganda, Kenya and Rwanda. Sweden confirmed its first case of mpox in Europe on Thursday.

Who is at risk?

In the wave of transmission in the Democratic Republic of Congo, children are the main victims: 70% of positive cases are among children under 15 years of age, and 39% are among children under five years of age, who account for 62% of deaths. However, the WHO wants to bolster monitoring of the virus to better understand how it is behaving, its epidemiological patterns and how and where infections are occurring.

What is known about the new variant?

The most worrying clade (variant) is 1b, which recently emerged in the Democratic Republic of the Congo. It appears to be more virulent and have higher mortality, especially among children. It is also showing greater capacity for human-to-human transmission. Clade 2 — which was responsible for the global outbreak in 2022 — continues to circulate, albeit with lower virulence, in regions of West Africa and other countries.

Is it more lethal?

Monkeypox has a fatality rate of between 0% and 11%. In the 2022 outbreak, the fatality rate was very low, usually affecting people with pre-existing illnesses. In this case, it appears to be higher, around 3% in Africa, and may reach 10% in some groups. It should be noted that the surveillance and health systems on the continent are not robust, meaning it is difficult to know to what extent the virus is intrinsically more deadly. It is also known that it is more dangerous in children, who account for a high percentage of those infected.

What are the symptoms?

The symptoms include fever, a widespread rash, and usually swollen lymph nodes. The WHO warns that it can be confused with other diseases such as the chickenpox, measles, bacterial skin infections, scabies, syphilis, and drug-related allergies. The incubation period for mpox ranges from five to 21 days. The febrile phase of the disease usually lasts one to three days, with symptoms including fever, severe headache, lymphadenopathy (swollen lymph nodes), back pain, myalgia (muscle pain), and severe asthenia (lack of energy). The febrile phase is followed by the rash phase, which lasts two to four weeks. Lesions progress from macules (flat-based lesions) to papules (firm, raised, painful lesions), to vesicles (filled with clear fluid), to pustules (filled with pus), followed by crusts or scabs.

How is it spread?

In the 2022 outbreak, the disease was spread through intimate contact, with most of the cases transmitted through sexual relations. This new variant appears to be more transmissible. Transmission can occur from person to person through close contact with someone infected: being face to face, talking or breathing near an infected person, skin-to-skin contact, mouth-to-mouth or mouth-to-skin.

How effective are vaccines against mpox?

The traditional smallpox vaccine was initially used, which in the past showed 85% effectiveness. A Spanish study showed 79% effectiveness in the 2022 outbreak. New vaccines better targeted at mpox have been developed with very promising results, but their effectiveness in real-world situations still needs to be measured more precisely.

Should the entire population be vaccinated?

No, only the population considered at risk. International health authorities are studying the contagion patterns of the new variant of the virus in Africa to determine which populations are at risk.

This list may include people who engage in risky sexual practices, who are at occupational risk such as healthcare personnel in specialist STI/HIV clinics who care for people with high-risk practices and laboratory personnel who handle samples potentially contaminated with the virus, as well as personnel in charge of disinfecting surfaces in specific premises where risky sexual relations take place. Post-exposure prophylaxis is indicated for all close contacts who have not had the disease.

Is there treatment?

Most treatments are aimed at mitigating symptoms. An antiviral developed to treat smallpox (tecovirimat) was approved in January 2022 by the European Medicines Agency for the treatment of mpox in exceptional circumstances. These treatments are increasingly being tested to address mpox, but their use is still limited and mostly confined to trials.

What is a health emergency of international concern?

This is the highest level of alert that the WHO has for a disease. It has been used eight times in history. The last time was to declare it in the outbreaks of MPOX that spread throughout the world, with a strong focus in Spain. It lasted from July 2022 to May 2023. Covid was also declared in this way on January 12, 2020, an emergency that officially lasted until May 5, 2023 after claiming more than 20 million lives, according to the WHO's own calculations. Although the emergency does not entail any obligation for countries, it facilitates their coordination and the purchase of vaccines by countries, with less bureaucratic procedures that slow down the process.

Why has this emergency been declared?

The decision was unanimous among the members of the WHO Emergency Committee. Several circumstances converge: the rapid spread of a new variant, the detection in countries that had never previously recorded cases of mpox, the fact that it affects vulnerable people such as children and pregnant women, and the risk that the WHO sees in the spread beyond Africa.

Are we facing a pandemic?

There is no official definition in international health regulations of what a pandemic is. It is not a technical term, but it is used to refer to an epidemic disease that spreads to many countries. On March 11, the WHO classified Covid as a pandemic, but this was a simple nomination that served to draw attention to the extent of the problem; it is not a scale of severity.

Could we be facing a Covid-like situation?

There are many differences with the coronavirus. Although the transmission mechanisms of the new mpox variant are not yet fully understood, what is known so far is that infection occurs through very intimate contact, while Covid is transmitted through the air. The mpox virus has been known for years, while the Covid virus was new, and there is already a vaccine for this disease. What’s more, mpox outbreaks have been contained in the past, which did not happen with SARS-CoV-2 when it began to spread.

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