The public health community has been awakened by the sudden appearance of monkeypox in 13 countries. Monkeypox is a milder cousin of smallpox that can cause small outbreaks in Africa, but is unlikely to be a big problem. Men who have sex with men make up a disproportionate number of the cases so far. The reappearance of poxviruses, a largely forgotten threat since the World Health Organization declared smallpox eradicated in 1980, is unnerving.
The United Kingdom has 20 confirmed cases of the current outbreak. More than 100 suspected cases were reported in Spain, Portugal, the United States, Canada, Sweden, Italy, Belgium, France, Germany, the Netherlands, Australia, and Israel. David Heymann, an epidemiologist at the London School of Hygiene and Tropical Medicine who helped eradicate smallpox and first worked on a large monkeypox outbreak in Africa 25 years ago, expects many more cases to come to light in the days to come.
The WHO's lead for poxviruses,Rosamund Lewis, says sexual transmission appears to be a factor in this outbreak.
Monkeypox is a misconception; the virus was discovered in a colony of research monkeys, but its natural hosts are rodents and other small mammals. The Democratic Republic of the Congo was the first place in the world to see the virus in humans in 1970. Sometimes an outbreak occurs in sub-Saharan Africa after someone comes in contact with an animal that has the disease. There were 47 cases of pet prairie dogs in the United States that were linked to imported prairie dogs.
Most people recover in a few weeks. The recent outbreak appears to involve the West African strain, which has a fatality rate of 1% in past outbreaks.
Lewis notes that the majority of the people who get an outbreak don't spread it to anyone else. The number of suspected cases seems to be surprisingly high, because this outbreak is on a broad geographic area.
Although rare and unusual, the outbreak is not likely to become a major threat to the general population.
There are blisters on the skin of a child and adult who contracted monkeypox in the United States. The CDC/Getty Images.
A traveler from Nigeria returned to the UK on 4 May with a case of monkeypox. The patient had monkeypox 3 days later. According to the UK Health Security Agency, the person had no connection to any of the other cases detected to date.
The first full genome of the virus was posted yesterday by a team led by João Paulo Gomes at Portugal's National Institute of Health. The Portuguese researchers were able to sequence the virus from a sample collected on 4 May, which means that the person who had the disease had no connection to the patient in the United Kingdom. The Portuguese doctors didn't test the sample until they learned of the unusual clusters of cases in the United Kingdom.
Few doctors have ever seen a case of monkeypox. Most doctors wouldn't think to test for it because it's similar to other diseases such as chickenpox and syphilis. The polymerase chain reaction assays can be used to probe samples for small bits of monkeypox viral DNA, which can be used to amplify it.
Nigerian researchers suspected that monkeypox might have been transmitted by sexual transmission because several patients had genital ulcers. The Spanish Ministry of Health's coordination center for health alert and emergencies says that all of the seven confirmed cases in Spain were MSM or trans people. There were 23 suspected cases reported by Spain today.
Most of the cases have perianal, perigenital, and mouth problems. There is no evidence that semen can transmit the virus.
None of the patients in Spain have become seriously ill. Two people have HIV infections that are well controlled with medication. There is no evidence that compromised immune systems played a role in the outbreak. For privacy reasons, health officials in affected countries have not offered much information about the people. Small groups on social media have used the occasion to make offensive remarks about gay, bisexual, and trans people.
Heymann says it is possible that monkeypox began to spread in MSM before May. He theorizes that transmission may have been at a very low level during the COVID-19 lockdowns.
Up to 30% of people were killed by smallpox, which was a major disease for centuries. The only human pathogen that has been eradicated is the virus, although samples still exist in Russia and the United States. The vaccine was stopped because of its risks in the 70s. One in 1 million people died from the vaccine's side effects, which included a labmade virus that replicates inside the recipient. The last year that a natural case of smallpox occurred was 1977.
Over the past 50 years, the number of people who have become vulnerable to monkeypox has increased. Some researchers are worried that monkeypox might evolve to fill the void left by smallpox. The new outbreak is the first one to take place on several continents at the same time.
In Europe and North America, there are two vaccines that protect against monkeypox. One, manufactured by Emergent BioSolutions, is similar to the vaccine used during the eradication campaign and can still cause severe disease and even death in people who have compromised immune systems. The other uses a non-replicating form of vaccinia that is designed to cause fewer side effects. It is the only vaccine approved for monkeypox.
The United Kingdom started to offer vaccines to health care workers who had been in contact with monkeys. Spain has yet to do so, according to Sim, who notes that the country's infectious disease clinicians have the personal protective equipment and experience to protect themselves. Massachusetts General Hospital, which is caring for the only confirmed case in the United States, has not offered staff a vaccine. Paul Biddinger, who heads the hospital's center for disaster medicine, says they too take appropriate precautions. Even though the United States has approved vaccines, clinicians can't prescribe them because they are in a national stockpile. It deems health care workers at the hospital in a risk category that doesn't warrant vaccine.
If a person is exposed to the monkeypox virus, the vaccines can be used to protect contacts of suspected or confirmed monkeypox cases. No countries have announced plans to do so. Both vaccines are in short supply.
The meeting between Heymann and nine other public health leaders from around the world this week was planned six months ago to discuss the need for more countries to stockpile its vaccine, given the increase in monkeypox cases over the past few years. Today we have some doses available and we are going to distribute them, but how do you want us to decide if they go here or there?
Severe cases of monkeypox can be treated with drugs. tecovirimat was the first drug approved by the FDA to treat smallpox after it proved safe in human trials and effective in animals. The FDA approved a second drug for smallpox last year.
Although drugs and vaccines offer hope for limiting the severity and scope of this outbreak, a WHO statement issued on 18 May cautions that they are not yet widely available.
A quote by Agam Rao has been replaced to better reflect her views.
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