Medications are not usually needed to treat smallpox. The disease is usually mild and most infected people will recover in a few weeks without the need for treatment. But there are vaccines that can be used to control smallpox outbreaks, which some countries are already using. And there are treatments for those who get quite sick with the virus.
Monkeypox belongs to the genus Orthopoxvirus, which includes smallpox. Fortunately, due to something called cross-protection, smallpox vaccines also work for smallpox.
Although the world was declared smallpox-free in 1980, many countries maintain stocks of smallpox vaccines for emergencies. For example, the smallpox vaccine is used to protect laboratory workers from accidentally coming into contact with smallpox virus (such as monkeypox or vaccine, a smallpox virus similar to smallpox but less harmful). . They are also preserved in the event of a terrorist attack that can use smallpox as a biological weapon.
The smallpox vaccine can be up to 85% effective in stopping smallpox virus infection if given before people are exposed to the virus.
There are two types of smallpox vaccine. Both types are based on the vaccine virus. An older type of smallpox vaccine contains the “live” vaccine virus. The main one in this group is ACAM2000, which is approved in the US to protect people from smallpox.
Although ACAM2000 cannot cause smallpox, the vaccine virus it contains can be replicated after vaccination, being transmitted from the vaccinated person to an unvaccinated person who comes in close contact with the injection site or with any liquid leakage until 21 days later.
This also means that ACAM2000 can cause many side effects and should not be given to at-risk groups, such as pregnant or lactating women, and those with weakened immune systems. People with weakened immune systems, including those with HIV, can get very sick from the vaccine.
The smallpox virus belongs to the same genus as the smallpox virus. Phanie / Alamy Stock Photo
The other “live” vaccine virus is the Aventis Pasteur smallpox vaccine. It is not formally approved, but may be made available if other supplies run out.
A newer type of smallpox vaccine, called Imvanex, contains a living but modified form of the vaccinia virus called Ankara vaccinia. Imvanex, manufactured by Danish biotechnology firm Bavarian Nordic, is licensed in the European Union to prevent smallpox.
In the United States, the vaccine is branded Jynneos and is licensed to prevent both smallpox and smallpox in adults at risk for these diseases. Jynneos has been used in the UK in previous cases of smallpox.
Because Bavarian Nordic vaccines are made in a modified form of the vaccinia virus, they are considered safe for people at risk.
It will usually take five to 21 days for someone who comes into close contact with an infected person to show symptoms of monkeypox (and most likely seven to 14 days), so it is difficult to know if they were vaccinated after someone has been vaccinated. exposed to the smallpox of the monkey will protect them completely. However, the recommendation in the United States and the United Kingdom is that after a risk assessment, people exposed to the monkeypox virus should be offered a modified dose of vaccinia Ankara vaccine. as soon as possible, ideally in four days, but up to 14 days later.
Antivirals
Aside from vaccines, there are some medications that could be used to treat monkeypox.
One of these drugs is tecovirimate, which stops the spread of infection by interfering with a protein found on the surface of Orthopoxviruses.
Tecovirimat is approved in the United States only to treat smallpox. It has been tested in healthy humans and has been shown to stop the smallpox virus in the lab. However, it has not been tested in people with smallpox or other orthopoxviruses. However, in Europe, the victim has been authorized to treat smallpox, simian smallpox and bovine smallpox in exceptional circumstances.
Another antiviral that can be used is cidofovir, an injectable drug authorized in the UK to treat a serious viral eye infection in people with AIDS.
In the body, cidofovir becomes the antiviral ingredient cidofovir diphosphate. Because cidofovir stops smallpox in the laboratory, it could be authorized for emergency use in smallpox or smallpox outbreaks.
However, cidofovir is a very potent drug and can damage the kidneys, so a better alternative could be the closely related drug brincidofovir, which has been approved in the US to treat smallpox.
Brincidofovir (brand name Tembexa) is administered orally and can be prescribed to people of any age. Its special design helps to introduce the right amount of the drug into the cells to release the cidofovir component and also makes it less harmful to the kidneys.
Brincidofovir has been tested in humans for other viral conditions. Its approval for use in smallpox in the United States comes from laboratory studies showing that it works against Orthopoxviruses. For this reason, brincidofovir is also listed as a potential drug for the treatment of monkeypox.
What we still lack, however, are data on the effectiveness of cidofovir, brincidofovir, and tecovitimat in treating monkeypox infections in humans. A recent article in The Lancet Infectious Diseases investigated the effectiveness of brincidofovir (three patients) and tecovirimat (one patient) in monkeypox cases between 2018 and 2021 in the UK. The researchers reported ineffectiveness of brincidofovir and called for more studies of tecovirimate in human smallpox infection.