The Centers for Disease Control and Prevention has identified 21 cases of monkeypox in 11 states, and the number is expected to grow, officials reported Friday.
Genetic analysis shows that while most cases are closely related to the European outbreak, two patients with a version of the virus appear to have developed from a confirmed case of monkeypox. in Texas last year.
Of the 17 patients for whom the agency had details, all but one were men who had sex with men; The 14 had traveled to other countries in the three weeks before their symptoms began. Three patients were immunocompromised.
CDC researchers were unable to determine how an unnamed patient contracted the virus. That suggests there’s community transmission going on at least in that state and possibly elsewhere, CDC’s Dr. Jennifer McQuiston told reporters.
“We want to really ramp up our surveillance efforts,” she said.
Health officials have identified a total of about 400 people in contact with the 13 patients who are also at risk for monkeypox infection. Identifying risk contacts will help officials determine what resources are needed to contain the outbreak.
To date, health officials have provided about 1,200 doses of the vaccine and 100 courses of treatment to eight states, according to Dr. Raj Panjabi, Senior Director of Global Health Security and Biosecurity. The White House.
The number of smallpox cases worldwide increased sharply this week, to nearly 800 on Friday. The spread of the virus to at least 31 countries outside of Africa, where it is endemic, has raised alarm among scientists and public health officials.
Health officials in several countries are requiring anyone who tests positive for monkeypox to isolate at home. The UK, the country with the most cases, has advised patients to abstain from sex until symptoms are gone, use condoms for eight weeks afterwards and limit interactions with pets and other animals. Other animals may be infected.
As the outbreak unfolds, health officials worldwide are rushing to gather vaccines and treatments to protect those infected and those in close contact with them. The options are severely limited.
The United States is one of the few countries that has stockpiled millions of doses of smallpox vaccines and drugs to prevent smallpox from returning. Smallpox in monkeys is closely related to smallpox, and vaccines and drugs are expected to be equally effective.
In theory, there are at least two drugs and two vaccines to combat the monkeypox outbreak, but most of them have been tested primarily on animals.
In a recent study of two drugs in seven patients, only one appeared to provide any benefit, while the other produced toxic side effects.
Two older vaccine options are used to eradicate smallpox and can cause serious side effects, including heart problems and death. Most doses have been preserved for decades and may have lost their effectiveness.
A second vaccine option, made by the Danish company Bavarian Nordic, was approved by the Food and Drug Administration in 2019 to prevent smallpox and smallpox in monkeys. Called Jynneos in the United States, it is safer than previous vaccines, but supplies are even more limited.
Several countries, including Canada, the UK and France, have begun vaccinating close contacts of infected people, and many more have placed orders to the Bavarian Nordic to provide additional supplies. .
Some experts note that African countries that have been battling monkeypox for years have little access to these vaccines and treatments. So far this year, 44 cases have been recorded in Nigeria and six other African countries where the virus is circulating, but those numbers are likely an underestimate.
Some experts fear that monkeypox outbreaks in Western countries could further limit access to vaccines and treatments in poor countries. Dr Ifedayo Adetifa, Director of the Nigeria Center for Disease Control, said: “Vaccines and treatments that are being stockpiled elsewhere are not necessarily shared.
In Switzerland, the World Health Organization maintains about 2.4 million doses of the vaccine used to eradicate smallpox, and the organization has stockpiled another 31 million doses in five donor countries to have Issued to countries in need.
However, WHO had previously recommended vaccinating only those at high risk of exposure, said Tarik Jašarević, a spokesman for the organization. “Experts convened by WHO were scheduled to review the guidance in October, but” that timeline would need to be accelerated, he said.
WHO is also evaluating the newer Jynneos vaccine for prequalification, a step needed for use in many countries.
CDC scientific advisors voted in November to recommend Jynneos to immunization researchers and health care workers at risk of exposure to smallpox or monkeypox.
The US emergency stockpile contains 100 million doses of an older smallpox vaccine called ACAM2000. But the vaccine contains a live immunized virus, and causes about six cases of myocarditis — inflammation of the heart muscle — for every 1,000 people injected.
ACAM2000 should not be used by pregnant women, infants, or immunocompromised individuals – precisely those who need protection from monkeypox virus.
In contrast, Jynneos has been shown to be safe in older adults, people with HIV or AIDS, and those who have had a bone marrow transplant and are therefore immunocompromised.
According to Paul Chaplin, chief executive officer of Bavarian Nordic, the US stockpile once contained 28 million doses of Jynneos, but those doses have all expired. Federal health officials say there are about 1,000 doses of Jynneos, but Bavarian Nordic has supplied thousands more in recent weeks, according to Dr. Chaplin.
In total, the US has about a million doses of the drug, he said.
People infected with monkeypox can be vaccinated even days after exposure. They can also be treated with one of two drugs approved to treat smallpox, tecovirimat and brincidofovir, which slow down the virus and give the immune system time to destroy it.
The FDA has approved the oral form of tecovirimat, also known as Tpoxx, to treat smallpox in adults and children who weigh at least 13 kg, or 28.6 pounds, although the drug has never been tested. in children.
Things to know about monkeypox virus
What is monkeypox? Monkeypox is a virus endemic to parts of Central and West Africa. It is similar to smallpox, but less severe. It was discovered in 1958, after an outbreak of disease in monkeys kept for research, according to the Centers for Disease Control and Prevention.
The drug, made by the New York-based company Siga Technologies, is taken twice daily for 14 days and in safety tests it appeared to have no serious side effects other than stomach symptoms.
US stockpile contains 1.7 million tecovirimat . courses. On May 12, before the monkeypox outbreak, the Department of Defense purchased an additional $7.5 million for drug courses, about half of which will be delivered this year.
“A significant number of countries have required drug courses since the outbreak began,” said Dennis Hruby, chief scientist of Siga. By the end of June, the company expects to have up to 190,000 courses of treatment to distribute, he said.
The FDA worked with Siga to develop an intravenous formulation and approved it on May 19. This version can be used for patients who cannot take oral medication due to blistering in the mouth.
Health Canada, the country’s national health department, approved tecovirimat in 2020 and purchased $13 million worth of doses of the drug, according to Dr. Hruby. The European Medicines Agency also approved the drug in January to treat all viruses that cause orthopox – a family of viruses that includes smallpox and monkeypox – but is still in talks with the company. during an outbreak.
Tecovirimat and brincidofovir have both been approved under the FDA’s Animal Rule, which allows the agency to rely on data from rodents or monkeys when it is unethical to test a drug in humans.
The second drug, brincidofovir, is made by Chimerix and appears to have more side effects, including a risk of death, prompting the agency to issue a so-called black box warning – the strictest warning – about drug use.
In a recent study of both drugs, researchers reported that brincidofovir “did not provide any compelling clinical benefit”. But the study was too small and the treatment regimens offered to patients were too varied to draw any conclusions about the drug’s effectiveness, said David Evans, a virologist at the University of Alberta who advises Chimerix said.
People who can’t safely take tecovirimat or brincidofovir – eg people who are immunocompromised – can get an immunotherapy called immunoglobulin, but that only exists in limited amounts. .
The United States is helping to develop a monoclonal antibody drug that could block the smallpox virus in monkeys. Several vaccines are also in the early stages of development, including some that are based on equine poison.
In the long term, the United States can stock enough vaccines and drugs to protect the entire population – including those who may have been vaccinated against smallpox as children, said Dr. Seth Lederman, chief executive officer of Tonix , said. is developing an antioxidant-based vaccine.
Many studies suggest that people who have been vaccinated against smallpox may be protected from serious illness, if not infection. But developing just a few lesions is enough to spread the virus to others, Dr. Lederman notes.
“In a case like smallpox in monkeys, I think the goal would be to leave people unscathed,” he added.
Tonix’s vaccine will not be available for use during the current outbreak. “Our approach will be to go slow and steady,” he said. “These problems are not going to go away.”
