On Thursday, May 19, it was reported that the rising cases of monkeypox (MPV) in the UK caused the authorities to use the smallpox vaccine on those who were exposed to the virus. Health workers were also given the vaccine to initiate protection against the MPV.
According to UK's Health Secretary Sajid Javid, Britain has seen eleven new cases on top of the existing nine cases, pushing the number of affected individuals to 20. Javid also tweeted an update on the vaccination. He mentioned:
"Most cases are mild, and I can confirm we have procured further doses of vaccines that are effective against monkeypox."
Meanwhile, Chief Medical Adviser of the UK Health Security Agency (UKHSA), Dr. Susan Hopkins, stated:
"We expect this increase to continue in the coming days and for more cases to be identified in the wider community. Alongside this we are receiving reports of further cases being identified in other countries globally."
Effectiveness of smallpox vaccine against monkeypox:
Health Secretary Sajid Javid's tweet revealed that UK has begun to stockpile smallpox vaccines, which can offer some protection against the MPV. According to certain medical and health authorities, including Britain's UKHSA and USA's CDC (Centers for Disease Control and Prevention), jabs meant for smallpox can work against the MPV, owing to their similar nature.
Both viruses belong to the same genus and are considered as Orthopoxviruses consisting of a double-stranded DNA genome. Furthermore, both viruses have similar symptoms, including fever, rashes, headaches, and more. They also cause pustules (pimples) or bumps all over the body. While the MPV is mild, the Congo variant has clocked around a ten percent mortality rate.
According to CDC,
"Because monkeypox virus is closely related to the virus that causes smallpox, the smallpox vaccine can protect people from getting monkeypox. Past data from Africa suggests that the smallpox vaccine is at least 85% effective in preventing monkeypox."
The agency also states that the vaccination may help even when it is administered after contracting the virus. In such cases, experts have reportedly found that the smallpox vaccine reduced the severity of the monkeypox virus (MPV). However, the jabs are most effective when administered before exposure to the virus. As of now, CDC has approved the usage of JYNNEOS' smallpox vaccine against MPV.
On their medical information page for clinicians, the CDC also recommended that the vaccine should be administered within four days of exposure to have the best chance of preventing the virus' progression. However, if the vaccine is given within four to fourteen days of contracting the virus, it may reduce some symptoms.
In regards to revaccination, the CDC stated:
"Persons exposed to monkeypox virus and who have not received the smallpox vaccine within the last 3 years, should consider getting vaccinated.
While vaccination is likely to pose no significant side effects to most people, the agency estimated that one to two individuals in a million might die from complications initiated by the vaccine. This estimate is allegedly based on their past experiences.