What to know about monkeypox and smallpox vaccines

What is happening
Vaccines are offered for people at higher risk of monkeypox, but doses are limited.
why is it important
Getting vaccinated before or after an exposure can reduce the risk of contracting the disease and slow its spread.
What this means for you
Some men who have sex with men are eligible for the vaccine, as are others who may have been exposed to monkeypox. Given the limited supply, you will likely only receive the first dose of the two-dose vaccine at this time.
More than 5,000 cases of monkeypox have been confirmed in the United States as of July 29, and that number is expected to rise as testing increases. To slow the spread of the disease, health officials are releasing doses of an approved vaccine for monkeypox and smallpox, but reports of problems with scheduling as demand outstrips supply have undermined the public health response.
In an effort to shift more resources to the outbreak, New York City – the epicenter of the monkeypox outbreak – has joined New York State and San Francisco in declaring monkeypox an emergency. sanitary. In a July 30 press release, New York City Mayor Eric Adams estimated that approximately 150,000 New Yorkers are currently at risk of contracting monkeypox. As of July 29, more than 1,200 people have tested positive for monkeypox in the city.
Jynneos, the vaccine shipping to states and cities, is primarily for men who have sex with men and others who may be exposed and are currently at higher risk during the outbreak. Federal officials have acknowledged that demand for the vaccine exceeds supply, and the US Department of Health and Human Services has shipped more doses to states. As of July 28, HHS said it had delivered 340,000 doses across the United States, with plans to release an additional 786,000 doses.
The federal government has promised that a total of 6.9 million doses will be available by mid-2023, but some critics have warned that the public health response to monkeypox has been far too slow and that at the time where these doses can reach people’s arms. , it may be too late to prevent the disease from spreading widely in the United States.
“We’re sort of catching up,” said Dr. Amesh Adalja, an infectious disease expert and senior fellow at the Johns Hopkins Center for Health Security.
In areas with many cases, such as San Francisco, New York and Washington, DC, people eligible for the vaccine only receive the first dose of the two-dose series. Officials say this will still offer protection against monkeypox and matches the response of other countries, including Canada and the UK.
Here’s what we know about the Jynneos monkeypox vaccine and who is eligible for it. Here’s also what you need to know about ACAM2000, the older generation vaccine that also works against monkeypox.
Read more: Monkeypox explained: symptoms, treatment and how it spreads
Vaccine requirements: Who is eligible for the monkeypox vaccine?
The exact criteria for determining who should get a monkeypox vaccine depends on the city or state people live in and the extent of the outbreak there, but men who have sex with men and who have had multiple or anonymous sex partners in the past two weeks are eligible in cities like New York. Indeed, most cases in the current outbreak are in gay and bisexual men, although anyone in close contact with monkeypox can contract the disease.
According to the CDC, you meet the criteria for a monkeypox vaccine if:
- You are a contact of someone who has monkeypox or you have been identified as potentially exposed via contact tracing.
- You have had a sexual partner within the past two weeks who has monkeypox.
- You have had multiple sexual partners in the past two weeks in an area with a high number of monkeypox cases.
- You are a laboratory or healthcare worker who comes into contact with orthopox viruses, including in animals.
If you’re concerned about monkeypox and think you might be at high risk for exposure, research your city and state’s current guidelines. You can also consult your doctor or book an appointment for the vaccine online, a process that will guide you through the eligibility criteria. This is the New York City vaccine appointment website. You can make an appointment and find a vaccine in San Francisco by calling one of the clinics in the city or visiting their meeting point.

A smallpox vaccine scar. People born before the mid-1970s may have such a scar. Jynneos, a next-generation monkeypox and smallpox vaccine, is not the same type of vaccine used to eradicate smallpox and does not leave a scar.
Photo Alliance/Getty Images
What are the monkeypox vaccines? Who is immune to the smallpox vaccine?
The United States has two vaccines that work against monkeypox in their national stockpile. Both are expected to work before exposure to monkeypox, as well as after exposure but before symptoms begin. (The fact that vaccines work after exposure distinguishes monkeypox from diseases like COVID-19.)
Jynneos (manufactured by Bavarian Nordic) is a next-generation vaccine approved by the US Food and Drug Administration in 2019 for monkeypox and smallpox. It is a two-dose vaccine, with each injection given four weeks apart. It uses a weakened virus and is approved for adults 18 and older who are at high risk of contracting monkeypox or smallpox.
Jynneos is the vaccine that is being shipped and currently being used in the US response to monkeypox. Due to limited supply, it is likely that you will only be able to book an appointment for the first dose at this time. In New York, for example, health officials say you will be contacted if you received a first dose about the second dose in the coming weeks.
ACAM2000 is a second-generation smallpox vaccine that also works against monkeypox. According to the CDC, ACAM2000 is a derivative of Dryvax, which helped eradicate smallpox. (The two diseases are closely related and both caused by orthopoxviruses, which makes this possible.) If needed, the U.S. Department of Health and Human Services said it is also ready to ship the ACAM2000 vaccine, which is more abundant than Jynneos but still a second choice in the answer to monkeypox because it has a side effect profile that is not safe for some people.
ACAM2000 is administered differently than the typical vaccine we are used to. It is administered by dipping a needle into a vaccine solution which is then ‘pricked’ several times into the upper arm. It will cause a localized infection (a “pox”), causing an immune response.
Although ACAM2000 does not cause smallpox, it does contain live vaccine virus, which is not suitable for everyone. It could be dangerous for immunocompromised people, pregnant women and people with certain heart or skin conditions, such as eczema.
Smallpox was declared eliminated from the world in 1980. The United States stopped routine vaccination against it in 1972, although some healthcare workers or people who work in laboratories may have had the vaccine. Historically, according to the CDC, smallpox vaccines were 95% effective against infection and protected you for about three to five years, after which the protection began to wane.
For this reason, it is possible that people born before the early 1970s who received the smallpox vaccine may have some cross-protective immunity against monkeypox, according to the WHO, but there is “little evidence.” ‘immunity’ for young people living in non-endemic countries because they’ve had no exposure to a similar virus.
How effective are monkeypox vaccines? How long do they take to work?
If Jynneos is given within four days of exposure to monkeypox, it is the best option for stopping the onset of disease, according to the CDC. If given four to 14 days after an exposure, the CDC says Jynneos may not prevent monkeypox, but will likely reduce the severity of your symptoms.
The CDC says the Jynneos vaccine takes two weeks (14 days) after the second dose for immunity to develop, and the ACAM2000 takes four weeks for peak immunity. Although many people currently only receive the first dose of Jynneos, early research suggests that one dose will still provide some protection, at least for a shorter period of time.
Because the U.S. monkeypox outbreak is so new, there is no data yet on the exact effectiveness of vaccines in the current situation, according to the CDC. The effectiveness of Jynneos against monkeypox is supported by animal studies, according to the agency. And although not used in most cases, ACAM2000 is closely related to Dryvax, the vaccine that helped get rid of smallpox. The effectiveness of ACAM2000 is supported by animal studies as well as human clinical trials.
You should always self-isolate if you develop symptoms of monkeypox after being vaccinated, such as a rash.

A computer image of a monkeypox virus.
Uma Shankar Sharma/Getty Images
Why does the United States have a stockpile of monkeypox vaccines?
The United States has a stockpile of Jynneos and ACAM2000 on hand not because the country feared an outbreak of monkeypox (which has been endemic in some African countries for years), but in case smallpox becomes a public threat again. . Smallpox was declared eliminated in the 1980s, and the last natural epidemic in the United States occurred in 1949. But smallpox is generally much more serious than monkeypox, and officials fear it is being used as biological warfare.
“The stockpile was created in the event of a biological weapons attack on the United States with smallpox,” Adalja said. In this case, health officials would not ration vaccines or only use the next-generation vaccine, Adalja said.
“If there was a smallpox attack, we would use all the vaccines we have to be able to deal with it,” he added.
The information in this article is for educational and informational purposes only and is not intended to constitute medical or health advice. Always consult a physician or other qualified health care provider with any questions you may have about a medical condition or health goals.
CNET