Mpox, formerly known as monkeypox, is a viral illness causing a painful rash, fever, and swollen lymph nodes, potentially leading to serious complications. The 2022 global outbreak highlighted vaccination’s importance in preventing transmission and reducing disease severity. Vaccines are a key tool in controlling mpox spread.
Recommended Vaccination Groups
Mpox vaccination is recommended for specific populations at higher risk of exposure or severe outcomes. Recommendations differentiate between pre-exposure prophylactic (PrEP) vaccination, given before potential exposure, and post-exposure prophylactic (PEP) vaccination, administered after known or suspected exposure.
PrEP vaccination is advised for individuals with ongoing mpox exposure risk. This includes gay, bisexual, and other men who have sex with men, and transgender or nonbinary people, who in the past six months have had a new sexually transmitted disease diagnosis, more than one sexual partner, sex at a commercial venue, or sex at a large public event in an area with ongoing mpox transmission. Sexual partners of individuals with these risks should also consider PrEP vaccination. Healthcare workers and laboratory personnel handling orthopoxviruses may also be recommended for vaccination due to occupational exposure. Individuals traveling to countries with active clade I mpox outbreaks who anticipate certain sexual exposures should also consider full vaccination.
PEP vaccination is for individuals with recent close contact with someone diagnosed with mpox. The vaccine should ideally be administered as soon as possible after exposure, preferably within four days, to help prevent disease onset. Vaccination between 4 and 14 days after exposure may still reduce symptom severity, even if it does not prevent illness entirely. Public health officials identify exposed individuals, who are then offered the vaccine to limit further spread.
Understanding the Monkeypox Vaccine
The primary vaccine for mpox prevention is JYNNEOS, approved for individuals aged 18 and older, and available under Emergency Use Authorization for those younger than 18. This vaccine contains a modified, weakened vaccinia virus, related to both mpox and smallpox. The modified vaccinia virus Ankara (MVA) cannot replicate in human cells, meaning it cannot cause mpox or smallpox in vaccinated individuals. Instead, it stimulates the immune system to produce a protective response against orthopoxviruses.
JYNNEOS is administered as a two-dose series, with doses given 28 days (four weeks) apart. Full protection is achieved two weeks after the second dose. While a single dose offers some protection, two doses provide significantly better immunity. Real-world data indicates JYNNEOS vaccine effectiveness against mpox ranges from 66% to 89% for individuals who have received both doses.
Common side effects after JYNNEOS vaccination are mild and temporary, indicating an immune response. These include pain, redness, and itching at the injection site. Some individuals may also experience systemic symptoms like fatigue, headache, muscle aches, nausea, or chills. Serious adverse events are rare, and safety monitoring systems have not identified new or unexpected safety concerns.
Finding and Receiving the Vaccine
Individuals seeking the mpox vaccine can consult their healthcare provider. Local public health department websites are valuable resources, often providing eligibility and clinic locations. Some regions may offer online vaccine finder tools to locate nearby vaccination sites.
The JYNNEOS vaccine is administered as an injection, typically in the upper arm. It can be given either subcutaneously (under the skin) or, for individuals aged 18 and older, intradermally (between the layers of the skin). The intradermal method uses a smaller vaccine volume while achieving a similar immune response, which helped conserve vaccine supply during the outbreak. For optimal protection, both doses are important, with the second dose given four weeks after the first; if delayed, receive it as soon as possible to complete the series, as there is no need to restart the vaccination schedule. Following vaccination, continue other prevention measures, such as avoiding close skin-to-skin contact with anyone showing mpox symptoms.