Dr. Adeola Fowotade, an Associate Professor (Reader) and a Clinical Virologist at the College of Medicine, University of Ibadan and the University College Hospital (UCH), Ibadan, in this interview with SADE OGUNTOLA explains the benefits of the Mpox vaccine and why individuals at high risk should get vaccinated.
M POX is declared a public health emergency, but what kind of disease is it?
Mpox is a viral disease caused by the Mpox virus, a member of the Orthopoxvirus genus, which also includes cowpox and smallpox. It usually starts with flu-like symptoms such as fever, headache, muscular pain, and swollen lymph nodes. This is followed by a distinctive rash that typically begins on the face and spreads to other body regions.
The virus can be transmitted through contact with contagious bodily fluids, skin rashes, or contaminated objects such as bedding, clothing, or towels. It can also be spread from animals to humans and from person to person, but it is less contagious than other viruses such as measles.
The severity of Mpox can vary. While many cases are mild and self-limiting, severe cases can occur, particularly in people with weakened immune systems, children and pregnant women. Factors that increase the risk of severe disease include a weakened immune system, underlying health conditions, and lack of access to healthcare.
Why is the Mpox vaccination helpful in containing its transmission?
Vaccination helps control the spread of Mpox, especially during outbreaks. It reduces the number of susceptible individuals and lowers the risk of widespread transmission. It is crucial for protecting high-risk groups, including healthcare workers, laboratory personnel, and those in close contact with infected individuals.
Vaccines are one of several tools used to interrupt transmission and protect children and communities against Mpox. It will reduce severe cases of Mpox, lowering complications and hospitalisations, especially among vulnerable or at-risk individuals such as men who have sex with men (MSM), immunocompromised people and healthcare workers.
Mpox vaccine can be administered as post-exposure prophylaxis (PEP) to those who have been exposed to the Mpox virus. The Mpox vaccination can also be administered to those who have particular risk factors or recent experiences that increase their chances of being exposed to Mpox. However, vaccinated people should continue to avoid close, skin-to-skin contact with someone who has Mpox.
While it is possible for people who have recovered from Mpox to get Mpox again, it’s very rare. Unpublished CDC data show that less than 0.1% of patients in the United States who previously had Mpox have been reinfected. Furthermore, the second time they contracted Mpox, the sickness was often milder than the first.
However, Mpox vaccination is mostly used for prevention, not treatment or cure. If you’ve already had mpox, vaccination could still be beneficial, especially if there’s a risk of re-exposure or if the previous infection was mild and may not have generated strong immunity.
What is the Mpox vaccine composed of, and how does it function in humans?
The vaccine is a live attenuated (weakened) virus from the same family as the smallpox virus. It induces the production of specific antibodies and activation of T-cells that can recognise and destroy cells infected with similar viruses. It also stimulates the immune system to create a “memory” of the vaccinia virus. This virus is related to the Mpox and smallpox viruses. If the person is later exposed to the Mpox virus, their immune system will be better prepared to detect and respond to identical viral proteins.
The Modified Vaccinia Ankara vaccine, developed in Germany in the 1950s and 1960s, was originally intended to defend against smallpox. Bavarian Nordic, a Danish biotech business, developed its current form, MVA-BN, which has been in production since 2010. It is administered in two doses, typically 28 days apart.
How effective is it? Does it confirm lifelong protection against Mpox?
The Mpox vaccine is highly effective in preventing infection and controlling outbreaks. However, it does not provide lifelong protection, and immunity may wane over time. Booster doses may be required to maintain appropriate protection, particularly for people at higher risk, beyond the length of immunity afforded by the original vaccination, or in the context of continuous outbreaks.
Booster vaccine doses are normally advised every two to 10 years if a person is still at risk of exposure.
After receiving the vaccination, practically everyone develops antibodies and should have adequate protection against Mpox. The vaccine also takes time to become effective. It may begin to act after a few days and should provide the most protection after around four weeks.
Results from vaccine efficacy trials show that vaccination provides a high level of protection against Mpox. Further studies on the use of vaccines for Mpox will provide additional information on the effectiveness of these vaccines in different settings.
Are there groups of people that shouldn’t take the vaccine, and why?
There is need for some caution in certain groups, such as those with severe allergies, immunocompromised individuals, pregnant or breastfeeding women, individuals with severe skin conditions, and very young children. Pregnant or breastfeeding women are generally advised to avoid this vaccine unless absolutely necessary.
Also, individuals that have recently received another live vaccine, such as the MMR (measles, mumps, and rubella) vaccine, should discuss with their healthcare provider when it is appropriate to receive the Mpox vaccine to avoid any potential interactions.
Which group of people should prioritise its use in Nigeria—is it only health workers?
A tailored vaccination strategy is frequently recommended. Healthcare workers are a key priority for Mpox vaccination because of their high risk of exposure, but other groups must also be prioritised. This includes; persons with close interactions to Mpox cases, inhabitants of impacted towns, high-risk populations, first responders, and visitors to outbreak areas. In addition, the vaccines are also for people who had sexual contact with someone in the past two weeks who has tested positive for Mpox, are in close contact with someone who has Mpox, or work in a laboratory that handles samples or animals with orthopoxvirus.
While there may not be specific recommendations for vulnerable groups beyond those listed above, vaccination could be considered for individuals with underlying health conditions that could complicate a mumps infection, depending on their risk of exposure.
Is it a single-dose vaccine? Are there things people must do before taking the vaccine?
The Mpox vaccination is normally delivered in a single dose. This single dose is usually adequate to provide protection against Mpox because it stimulates the immune system to respond efficiently to the virus. Booster doses might be given as needed. While it is ideal to acquire the vaccination before being exposed to Mpox, getting it later may still help to prevent the disease or make the symptoms less severe.
What are the possible side effects and other things people should expect after taking the vaccine?
The Mpox vaccine, particularly the JYNNEOS vaccine, is generally considered safe, but like all vaccines, it can have side effects, and there are certain considerations that people should be aware of. As with most vaccines, common side effects of the Mpox vaccine can include soreness or redness at the injection site, mild fever, fatigue, and headache. These are usually mild and resolve within a few days. Less common side effects include skin reactions and muscle pain, while rare severe reactions might include allergic responses.
Any reason to fear the Mpox vaccine? The antivaxers are always quick to say that vaccines are for population control or to cause infertility.
Some people might fear the Mpox vaccine due to myths and misinformation about how vaccines work or their safety. It’s important to rely on credible sources and healthcare providers for accurate information. Vaccinations for smallpox (from which Mpox vaccinations are derived) have a lengthy history, and previous vaccines used decades ago had more severe adverse effects. However, recent vaccinations, such as JYNNEOS, have improved safety ratings. Hence, the fears about vaccines being used for population control or causing infertility are false. The Mpox vaccine, like other vaccinations, is designed to protect against sickness and has been thoroughly tested to assure its safety and efficacy. Even after vaccination, it’s important to continue following public health guidelines to avoid exposure to Mpox, especially in a high-risk environment.
Is the Mpox vaccine age-specific? Can children and the elderly take the vaccine?
The Mpox vaccines are safe to use for people aged over 18 years and over. Although the Mpox vaccine is not age-specific and can be given to both youngsters and the elderly, there are some considerations for each age group.
The Mpox vaccine can be administered to children, particularly those who are at high risk of exposure or live in a community suffering an outbreak. However, the vaccine’s use in children under the age of 18 may be determined by specific health authority guidelines and the availability of safety evidence for that age group. Older adults, particularly those with compromised immune systems or other health conditions, may be at higher risk of severe illness if they contract mpox, so vaccination is important.
If you have had Mpox before, do you still need to take the vaccine?
While having had Mpox provides some immunity, getting vaccinated may still be advantageous for better and prolonged protection. However, the vaccine does not treat or cure a current Mpox infection.
Natural immunity following an Mpox infection may minimise the chance of reinfection, but it may not guarantee permanent protection. In areas with ongoing outbreaks or for individuals at high risk of exposure, vaccination might be recommended even after a previous infection.
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