The Africa Centers for Disease Control and Prevention and the World Health Organization (WHO) have declared the recent outbreak of Mpox in Africa a public health emergency. An epidemic in the Democratic Republic of Congo has spread to neighboring countries, with more than 1,400 new Mpox cases detected in just one week. Vaccination is one of the most important strategies to contain the disease.
Virologist Anna-Lise Williamson explains how vaccines have evolved and who should be first in line in any vaccination campaign.
What vaccines are there against Mpox?
Monkeypox virus (MPXV), the virus that causes the disease Mpox, is related to the virus that causes smallpox. In addition to the viruses that cause smallpox and Mpox, there are a number of others in the orthopoxvirus group that infect humans, including cowpox virus, camelpox virus, and vaccinia virus.
The smallpox vaccine can protect against both MPXV strains: clade I and II.
Following an intensive global vaccination campaign, smallpox was eradicated worldwide in 1980.
The last smallpox vaccinations in Africa were administered around 1980. This means that today a younger, unvaccinated population is susceptible to MPXV infection.
The old smallpox vaccines were based on the vaccinia virus and can have serious side effects and, in rare cases, even be fatal.
The eradication of smallpox meant that there were no longer routine vaccinations to prevent the disease. However, the threat that this virus could be used as a biological weapon or that an unforeseen outbreak of the disease could occur led many countries to build up vaccine stockpiles. For example, the Strategic National Stockpile in the United States has enough smallpox vaccine to vaccinate every person in America against smallpox.
What are next generation vaccines?
A transition to next-generation vaccines, which have a better safety profile, is currently underway.
These include a vaccine called Jynneos in the US and Imvanex in Europe, which was widely used during the Mpox outbreak in 2022.
However, they also have disadvantages: their protection may not last as long, they are not yet approved for children, they are expensive and there are few of them.
Another vaccine that has recently become available is LC16 T. It is approved for use in children.
What are the obstacles to vaccine distribution in Africa?
Cost: Bavarian Nordic, manufacturer of the Jynneos vaccine, sold its vaccine for $110 per dose during the 2022 epidemic.
Low-income countries do not have the budget to procure these vaccines and are therefore forced to wait for WHO approval. Once this is granted, Unicef and the Global Vaccine Alliance will be able to procure the vaccines for use in poorer countries. To speed this up, WHO Director-General Tedros Adhanom Ghebreyesus initiated an “emergency use authorization” process for Mpox vaccines to speed up the availability of these drugs to people affected by this public health emergency.
Availability: The Mpox vaccines are all in short supply as the US, Canada and Europe purchased vaccines to contain the spread of Mpox in their high-risk populations.
MPX outbreaks have occurred in Africa for many years, but only recently have efforts been made to provide vaccines to vulnerable populations.
Jean Kaseya, director general of the Africa Centres for Disease Control, said Africa needs 10 million doses to stop the spread of MPXV.
It is unlikely that there will be vaccines for the entire population. Surveillance needs to be strengthened to identify the factors responsible for the spread of the virus so that vaccination campaigns can be targeted at those most at risk.
This should include preventive vaccinations to stop the spread of MPXV, as well as post-exposure vaccination for those most at risk. These include people with multiple sexual partners, as well as healthcare and laboratory workers.
People in overcrowded health facilities and in camps for displaced persons should also be specifically targeted.
Many children become infected with Mpox and die as a result. It is urgent that Mpox vaccines be approved for use in children.
