New Mpox Strain Identified in England: Combining Two Virus Types | ASHASexualHealth.org
- Public health officials in England have identified a new, combined type of mpox in an individual recently returned from Asia.
- Mpox, formerly known as monkeypox, is a viral infection related to the smallpox virus.
- Transmission occurs through direct contact with these sores, or with fluids from the sores that may remain on contaminated items like clothing or bedding.
Public health officials in England have identified a new, combined type of mpox in an individual recently returned from Asia. While details about the patient remain undisclosed, testing reveals the virus is a unique hybrid of the two known mpox clades, raising concerns among experts about potential future spread.
Understanding Mpox
Mpox, formerly known as monkeypox, is a viral infection related to the smallpox virus. Initial symptoms typically include fever, headache, muscle aches and backache. These may be followed by swollen lymph nodes and general exhaustion. Within a few days, a rash or sores often appears, initially on the face before potentially spreading to other parts of the body.
Transmission occurs through direct contact with these sores, or with fluids from the sores that may remain on contaminated items like clothing or bedding. The virus can also spread via saliva and respiratory secretions, meaning close contact such as kissing can facilitate transmission.
Two Main Clades: IIb and Ib
Currently, two main genetic groups of the mpox virus are circulating globally: Clade IIb and Clade Ib.
Clade IIb Mpox
Clade IIb was responsible for the widespread outbreak that occurred globally in 2022, infecting approximately 114,000 people and causing 220 deaths worldwide. In the United States, cases peaked in the summer of 2022, reaching 11,000 cases per month. This clade is generally considered less severe, causing mild symptoms and carrying a mortality rate of around 1%.
While mpox originates in animals, Clade IIb demonstrated person-to-person transmission during the 2022 outbreak, primarily through sexual contact among men who have sex with men.
Clade Ib Mpox
Clade Ib causes a more serious illness, with a fatality rate of approximately 10%. This clade has been present for years in the Democratic Republic of Congo (DRC). Historically, transmission occurred directly from animals to humans through activities like butchering and consumption. However, a recent outbreak that is now spreading person-to-person. In some regions of Africa, transmission is occurring within families through daily household activities and in healthcare settings due to inadequate protective equipment. A concerning trend is the increasing number of cases reported in children under the age of 15.
Notably, Clade Ib is now being transmitted sexually in some areas, with a significant proportion of cases observed among sex workers and transient populations like truck drivers.
Between and , over 48,000 cases of Clade Ib mpox were reported in Central and Eastern Africa. Approximately 43 cases have been identified in other countries, with roughly half linked to recent travel to Africa. However, 24 cases were detected in individuals with no reported travel history.
The World Health Organization (WHO) now believes Clade Ib mpox is spreading locally in Italy, Malaysia, the Netherlands, Portugal, Spain, and the United States.
The New Recombinant Strain in England
Genomic testing has revealed that the individual in England is infected with a strain of mpox that incorporates elements of both Clade IIb and Clade Ib. Here’s termed a recombinant virus, formed by the combination of genetic material from both clades. Experts acknowledge that the emergence of such a recombinant strain is not entirely unexpected, given the ongoing circulation of both virus types.
The primary concern is that viral evolution can complicate efforts to prevent further spread. Dr. Boghuma Titanji, assistant professor of medicine at Emory University, told the BBC
that this development represents a feared scenario: “The more mpox circulation we permit, the more opportunities the virus has to recombine and adapt, further entrenching mpox virus as a human pathogen that is not going away.”
Vaccination Remains a Key Strategy
A vaccine, JYNNEOS, is available to protect against both mpox and smallpox infections. The vaccine is administered in two doses, four weeks apart. Vaccination reduces the risk of contracting and spreading mpox, and can lessen the severity of symptoms if infection occurs.
The Centers for Disease Control and Prevention (CDC) recommends the mpox vaccine for gay, bisexual, transgender, or other men who have sex with men who have had (in the last six months) or anticipate having:
- One or more sexually transmitted infections
- More than one sexual partner
- Anonymous sexual or intimate contact
- Sex at a commercial sex venue
- Sex in association with a large public event in a geographic area where mpox transmission is occurring
A vaccination campaign targeting individuals meeting these criteria played a significant role in controlling the spread of mpox in the United States in .
Individuals who meet the CDC criteria and have not yet been vaccinated are encouraged to do so promptly. While this new recombinant strain has not yet been detected in the United States, both Clade IIb and Clade Ib continue to circulate at low levels.