Smallpox vaccines may also provide cover against mpox

By H. Hasan
Following confirmation of detection of at least thee mpox cases by Khyber Pakhtunkhwa health authorities, all in individuals returning from an Arab country, the Pakistani government has ramped up surveillance efforts at airports and border entry points, directing officials to set up isolation wards, stockpile antiviral medications, and provision of personal protective equipment (PPE) to healthcare workers in all medical facilities.
Pakistan has previously encountered mpox cases, the specific variant in these patients remains unclear.
As a precaution, samples from close contacts of the infected individuals have also been collected for further testing to prevent the virus from spreading.
On a global scale, the European Union, United States, Canada, and other countries had approved the MVA-BN vaccine in 2022 during the first declared global health emergency for mpox.
The existing vaccines were not specifically developed for monkeypox virus that belongs to the Orthopoxvirus genus, which also includes the smallpox virus (variola virus), cowpox virus, and vaccinia virus. Due to the genetic similarities among these viruses, vaccines originally designed to protect against smallpox can also offer protection against mpox.
Mpox vaccines work through a process known as "cross-reactivity," where the immune system recognizes similar structures among different viruses. For instance, antibodies generated against the smallpox virus can also protect against Mpox due to the structural similarities within the Orthopoxvirus family.
If a person has received the smallpox vaccine, you may have some level of protection against mpox, though it is not guaranteed. 
The global smallpox vaccination campaign ended in the 1980s after the disease was declared eradicated. Consequently, persons born after the campaign's conclusion, particularly men aged 18-44, showed a higher rate of mpox cases during the 2022-2023 global outbreak. 
The smallpox vaccine is estimated to be about 85pc effective against mpox, with those vaccinated generally experiencing milder symptoms if infected.
So far the primary vaccine approved for mpox across the EU, UK, US, Switzerland, and Canada is the MVA-BN (Modified Vaccinia Ankara-Bavarian Nordic) vaccine, which was originally developed in the 1950s and '60s in Germany, and has been modified by the Danish biotech company Bavarian Nordic. It is administered in two doses, typically 28 days apart.
Other vaccines, such as Japan’s LC16 and Russia’s OrthopoxVac, have also been approved for mpox prevention. The ACAM2000 vaccine, which contains a live vaccinia virus, is recommended in the US and Australia for individuals at risk of Orthopoxvirus infections.
The development of new vaccines is underway, that include an mRNA vaccine, BNT166, which specifically targets monkeypox virus antigens. This vaccine is still under clinical evaluation. However, the World Health Organization (WHO) does not recommend mass vaccination for mpox at this time, advising instead that only those at risk or who have been exposed to the virus should be vaccinated.