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Though monkeypox remains an incredibly rare virus, there are several vaccines currently available that can, at a minimum, protect against severe outcomes. Morsa Images/Getty Images
  • Currently, there are two available vaccines that protect against both smallpox and monkeypox.
  • One of the available vaccines, JYNNEOS, is FDA-approved for the prevention of both smallpox and monkeypox.
  • According to experts, the FDA-approved smallpox/monkey vaccine is around 85% effective and likely more effective in the prevention of severe disease.

As monkeypox cases grow throughout the United States with at least 45 confirmed cases, many are starting to wonder about a possible vaccine.

There are several modern vaccines available to help control the monkeypox virus family, however, not all of them are currently available and none are widely available to the public.

Today it was announced that the U.S. government put in an order for at least 500,000 doses of the JYNNEOS vaccine that can protect against both monkeypox and smallpox, according to the pharmaceutical company Bavarian Nordic.

The first vaccine against smallpox, made about 50 years ago, was thought to have provided some level of protection against monkeypox. This was a strong vaccine that had many side effects, and since then, newer vaccines have been developed.

“The original smallpox vaccine provided at least partial protection against monkeypox, however, it has been a long time since many people in our population have been vaccinated using this vaccine,” says Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center in Tennessee.

ACAM2000 is a vaccine that was created for smallpox but also has some cross coverage with monkeypox. This vaccine is approved for people who are 18 and older and are at high risk for smallpox infection. For monkeypox, this same vaccine can be “used in people exposed to monkeypox if used under an expanded access investigational new drug protocol,” according to the CDC.

Most recently, the FDA has approved JYNNEOS to prevent the spread of both monkeypox and smallpox.

This vaccine is approved to help prevent the viruses in adults 18 years and older who are at high risk for infection. It is administered as a two-dose regimen 4 weeks apart.

“JYNNEOS is expected to be at least 85 percent or so effective at the prevention of monkeypox and more effective at the prevention of severe monkeypox,” says Dr. Amesh Adalja, Senior Scholar at Johns Hopkins Center for Health Security.

Although not directly studied in pregnant human subjects, animal studies in rabbits show that this vaccine has no evidence of harm to a developing fetus. It is, however, unknown if this vaccine is safe for breastfeeding.

Schaffner explains that both vaccines may be used after exposure to help prevent severe illness.

“If you give it early enough after exposure it can either abort the infection completely or make it much less serious,” he says.

The first dose needs to be given within the first four days of exposure to help prevent disease onset, but if given between four and 14 days after exposure, it can help reduce symptoms, but it may not prevent disease.

Although both vaccines are useful in the prevention and control of monkeypox, Adalja says the JYNNEOS vaccine produces fewer side effects and is “safer in certain populations than ACAM2000” and will likely be the vaccine of choice between the two.

“In this outbreak, the vaccine is being deployed to close contacts of individuals with confirmed monkeypox cases,” Adalja tells Healthline.

The United Kingdom is currently offering vaccines, however not to the public. It is currently isolating those with confirmed infections and offering the vaccine to close contacts to help prevent the spread.

Schaffner tells Healthline that the makers of JYNNEOS are actively making the vaccine as “many countries in Europe are likely reaching out to them for supply.”

There are other manufacturers such as Tonix Pharmaceutical who are developing new ways to vaccinate the public against pox viruses, but currently, these vaccines are still in development.

Aside from vaccines, there are other measures that can be taken to prevent monkeypox, according to the CDC.

Avoiding people with known monkeypox is the first step someone can take to avoid the virus. Similarly, if you know someone who has been potentially exposed, avoid close or intimate contact until the incubation period of up to three weeks has passed.

As with most bacteria and viruses, good hand hygiene after contact with infected animals or humans is important. This includes washing your hands with soap and warm water or using an alcohol-based hand sanitizer.

You can avoid contact with animals who may have been exposed to the virus or been found dead in areas where monkeypox is endemic. Additionally, avoid contact with any materials such as bedding, which has touched a sick animal with monkeypox.

Health experts continue to monitor the spread of monkeypox. Although the number of monkeypox cases is increasing and a highly capable vaccine is available, the need for mass vaccination is not necessary at this time.

Monkeypox is an endemic virus to West and Central Africa and is part of the same family of viruses that cause smallpox and cowpox.

However, despite this being a rare virus, there have been past outbreaks in the United States. Last year there were two travel-related cases of monkeypox from Nigeria in the United States and 47 cases in 2003.

According to the World Health Organization, there are two clades, or forms, of monkeypox — the West African and the Congo Basin, or Central African. The Central African clade has a mortality rate of 10 percent and the West African form has a fatality rate that’s less than 1 percent.

Although most people experience mild symptoms and resolve without complication, children, the elderly, and those that are immunocompromised face the greatest chance of death or debilitating illness from this virus.

While both can have severe side effects, the West African clade, or the milder form, is the responsible strain for this outbreak.

Dr. Rajiv Bahl, is an emergency medicine physician, board member of the Florida College of Emergency Physicians, and health writer. You can find him at