Mpox, formerly known as monkeypox, has gained attention in recent years due to its potential for serious illness and global spread. After a recent outbreak in Africa, it was declared a Public Health Emergency of International Concern (PHEIC) on Aug 14, 2024 by the World Health Organization (WHO) Director. Vaccination is a key strategy in addressing this public health issue. The Jynneos vaccine has emerged as an important tool in the fight against mpox, offering protection against this virus.

The Mpox Virus:

Mpox is a viral disease caused by the mpox virus, which belongs to the same family as the virus that causes smallpox. Mpox was first identified in laboratory monkeys in 1958. The first human cases were reported in the Democratic Republic of the Congo in 1970. Mpox human-to-human transmission is spread through direct contact with bodily fluids or skin lesions of an infected individual. Transmission can also occur by touching contaminated materials, or close contact with infected wild animals.

The disease typically presents with symptoms such as fever, headache, muscle aches, swollen lymph nodes, and a characteristic rash. Symptoms of Mpox resolve within a few weeks in most cases. However, in some people, the illness can be severe and lead to complications, even death. Younger children, people who are pregnant, and people with immune deficiencies may be at higher risk of more serious mpox complications.

The Jynneos Vaccine:

Jynneos is a vaccine developed by the Bavarian Nordic that was approved by the Food and Drug Administration (FDA) in 2019 for the prevention of smallpox and mpox disease in adults 18 years of age or older. The vaccine contains a live, attenuated (weakened) virus. Jynneos works by stimulating the body’s immune system to produce protective antibodies against mpox and smallpox viruses. This allows the immune system to recognize and respond to the mpox and smallpox, preparing it to fight off the infection if exposed in the future.

The Jynneos vaccine is administered as a series of two subcutaneous injections, given four weeks apart. Full protection is typically achieved two weeks after the second dose. The vaccine has been shown to be effective in preventing mpox.

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Common side effects of the Jynneos vaccine include:

• Injection Site Reactions: Redness, swelling, and pain at the injection site are the most common side effects, but they are usually mild and resolve on their own.
• Fatigue
• Muscle Pain
• Headache
• Nausea

Who Should Get Vaccinated?

Currently, the Centers for Disease Control and Prevention (CDC) does not recommend routine immunization against mpox for the general public. The Jynneos vaccine is recommended for specific groups who are at increased risk of mpox exposure. These may include:

• Healthcare Workers: Those who may come into contact with mpox patients or laboratory specimens containing the virus may be considered for vaccination.
• Close Contacts of Mpox Cases: Vaccination may be recommended for those who have been in close contact with confirmed or suspected mpox cases. This includes those who have had sexual or intimate contact with someone who may have mpox.
• Travelers who are at high risk may be assessed for vaccination by their healthcare provider on a case-by-case basis.

Conclusion:

Mpox vaccination not only protects individuals at high risk of contracting the virus, but also contributes to broader efforts to control and prevent outbreaks. Having an effective vaccine like Jynneos is crucial for mitigating the impact of the disease and preventing future spread. The availability of the Jynneos vaccine is a significant advancement in public health efforts to prevent mpox. For those at high risk, the Jynneos vaccine provides protection against a disease that, while rare, can have serious consequences.

Resources:
1) Adepoju, Paul. Mpox declared a public health emergency. The Lancet, Volume 404, Issue 10454, e1 – e2. DOI: 10.1016/S0140-6736(24)01751-3.
2) https://ndc.services.cdc.gov/case-definitions/monkeypox-virus-infection-2023/#:~:text=Mpox%20(previously%20named%20monkeypox)%20is,vaccine)%2C%20and%20cowpox%20virus.
3) https://www.cdc.gov/poxvirus/mpox/clinicians/clinical-recognition.html
4) https://www.who.int/news-room/questions-and-answers/item/mpox#:~:text=Complications%20can%20include%20severe%20bacterial,pneumonia)%2C%20and%20eye%20problems.
5) JYNNEOS (Smallpox and Monkeypox Vaccine, Live, Nonreplicating) suspension for subcutaneous injection [package insert]. Denmark: Bavarian Nordic; 2023.
6) GARDASIL®9 (Human Papillomavirus 9-valent Vaccine, Recombinant) Suspension for intramuscular injection [package insert]. Rahway, NJ: Merck & Co., Inc; 2014.