On july 23rd the World Health Organisation (who) declared the spread of monkeypox a “public health emergency of international concern”, the highest level of alert in its hierarchy of warnings. The committee advising Tedros Adhanom Ghebreyesus, the who’s director-general, did not reach a consensus on whether to elevate monkeypox to that level, with six of its members in favour of doing so and the remaining nine opposed. Nonetheless, Dr Tedros decided to declare an emergency. He hopes that global efforts to curb the spread of the virus will now intensify. The designation gives the who more power to co-ordinate action to stop transmission.
Until this year monkeypox was primarily a zoonotic disease confined to parts of Africa, where transmission happened mainly from infected animals to people who hunted or ate them. Person-to-person transmission was rare. In May, however, cases began popping up in European countries, alarmingly in people with no direct links to travel from Africa. The outbreak was sustained through transmission between humans–and spreading. By July 23rd there were more than 16,000 reported cases in 75 countries and territories.
The virus causes flu-like symptoms and skin blisters from which the virus sheds. People can pick it up from infected bedding, clothes or utensils, but scientists think that skin-to-skin contact is the primary route of transmission. Large respiratory droplets can also spread the disease. In the current outbreak about 70% of cases are in Europe and 15% are in America, though far more limited testing in other regions means that transmission chains there may be going undetected. Disease experts reckon that the cases that are identified may only be the tip of an iceberg. In parts of Africa known cases are probably the most severe ones, involving people who show up at hospitals. That probably explains, at least in part, the higher mortality among monkeypox cases in Africa (where as many as 3-6% of cases can be fatal). There have been no deaths so far among the thousands of cases diagnosed in Western countries. Only 114 of more than 10,000 cases in Europe have needed clinical care at hospital, usually pain relief or treatment of bacterial infections in the blisters. An antiviral medicine called Tecovirimat is being used in America and Europe.
The current outbreak in America and Europe is almost entirely concentrated among men who have sex with men (some of whom do not identify as gay or bisexual). Disease investigators have found that, at least for now, many cases occur through male sexual networks, such as “sex-on-site” parties in saunas and clubs. About 99% of cases outside of Africa are men, most of whom are young or middle-aged. Among monkeypox cases who disclosed their sexual orientation to disease investigators in England, 97% were men who have sex with men. About half of them have had another sexually transmitted infection in the past year and a third said they had had ten or more sexual partners in the past three months. The overall profile of cases is similar in America and continental Europe.
Scientists are still trying to work out the ways in which the disease is caught. It is already clear that the virus does not spread easily through respiratory droplets. In the current cohort of monkeypox patients it has transmitted almost entirely through skin-to-skin contact, including sex. Occasional cases among household members of patients have been diagnosed, but they have been rare. That revelation prompted Britain’s public health authorities to change their isolation advice for contacts, so those without symptoms no longer need to go into quarantine. That the outbreak is concentrated in those very specific groups of men is, in some ways, beneficial. They tend to seek health care frequently, often for HIV treatment or for pre-exposure prophylaxis, a pill to prevent infection with hiv. They have readily lined up for the monkeypox vaccine, which many countries are offering to those in high-risk groups. But there are fears that the virus may cross over into other groups, just like HIV did. In America, where HIV spread among gay men first, a quarter of new cases now are among women.
The WHO’s emergency alert will draw attention to how monkeypox vaccines are being distributed around the world. The jab used for the disease now, made by Bavarian Nordic, a Danish company, was originally developed for smallpox, a related virus that was eradicated through mass vaccination in the 1970s. It has been used against monkeypox in America and Europe based on limited data of efficacy from monkeypox outbreaks in Africa. About half of countries that are currently reporting monkeypox cases have secured some amount of the vaccine, says the who. One of its tasks now is to ensure that the supplies rolling off production lines are sent to where they are needed the most. If countries’ tussling for covid-19 jabs in the early days of the pandemic is a guide, that will be the organisation’s toughest job. ■
