In this video from MedCram, Dr. Seheult discusses a new mRNA vaccine for Mpox. Moderna has created a new mRNA vaccine. The WHO had recently declared a public health emergency of international concern which as previously discussed in an earlier video was primarily done to mobilize resources and as an international effort to try and keep Mpox under control. Now the first vaccines are arriving to where they are needed in Africa in September 2024. The delay for the vaccines has to do with red tape and getting approval of the vaccines per this NPR article. At this time though, the WHO hasn’t approved any of the vaccines yet for Mpox and are still reviewing them.
What types of vaccines are available for Mpox?
Currently there are now 3 vaccines available named ACAM 2000, Jynneos and now Moderna’s mRNA. The ACAM 2000 is a live vaccine and uses the Vaccinia virus which is in the same family as Mpox. So vaccination against one gives immunity against others in the same family (the Orthopox family). The vaccine is not a clean vaccine and there is a risk that 1 out of every 175 persons can get myopericarditis. This was originally stockpiled for a smallpox outbreak which can have a mortality of up to 30%. Another vaccine is Jynneos which is a live attenuated vaccine and also based on the Vaccinia virus but it is nonreplicating. The rates of myopericarditis are extremely low. This vaccine has been the main vaccine used for at risk persons to vaccinate against Mpox. Now Moderna is providing a third vaccine via mRNA methods. This is not a live virus.
Types of Mpox clades
The Western African clade is known as the Clade IIb and has 99.9% survival and was at the center of the outbreak in 2022. In Central Africa is the Clade Ib which has had up to 10% mortality in the past. Recently there was a hospital where there were 400 patients with Mpox of the Clade Ib and only 4 of them died so currently the fatality rate is still around 1% based on the recent data. The only other countries that had reports of Mpox were in Sweden and Thailand from people who had traveled from these areas in Africa.
Comparison of vaccines
In this article, the study does a comparison of vaccines between a mRNA or a modified vaccinia Ankara vaccination in non human primates. The latter vaccine is referring to the same vaccine family as Jynneos. The mRNA vaccine uses 4 different proteins that were expressed and preserved and seen across the Orthopox family. The study showed that none of the monkeys that were vaccinated with either vaccine died. The other aspect to look at was the morbidity, in this case how many pox lesions were present. In the control group there were about 1600 lesions, in the Jynneos vaccine there were 600 and in the mRNA it was no more than 50-60 lesions. This study is part of the new mRNA vaccine pathway to acquiring FDA approval; however, it does seem that the mRNA vaccine will hold its own against the more traditional vaccine.
Currently none of these vaccines are recommended for the public in the United States except in high risk populations.
LINKS / REFERENCES:
First doses of mpox vaccines arrive at the heart of Africa’s outbreak. What took so long? (NPR) | https://www.npr.org/sections/goats-an…
About Mpox (CDC) | https://www.cdc.gov/poxvirus/mpox/abo…
ACAM2000 (Smallpox Vaccine) Questions and Answers (FDA) | https://www.fda.gov/vaccines-blood-bi…
Comparison of protection against mpox following mRNA or modified vaccinia Ankara vaccination in nonhuman primates (Cell) | https://www.cell.com/cell/fulltext/S0…
Moderna’s First mRNA Mpox Vaccine Beats Licensed Rival Shots In Early Testing (Forbes) | https://www.forbes.com/sites/robertha…