Human monkeypox virus (MPXV) is a double-stranded DNA virus of the family Poxviridae. Two subtypes of the virus have been identified: West African and Central African. MPXV is one of the orthopoxvirus species that infect humans. Another well-known one is variola major virus, which causes smallpox and has been eradicated.
What is monkeypox?
MPXV was first detected in 1958 in an outbreak among monkeys transported to Copenhagen, Denmark, from Africa for research purposes, hence the name ‘monkeypox’. However, this is not appropriate, since the main actual reservoirs (populations carrying the causative agent of a disease) of the virus are rodents such as squirrels, dormice and pouched rats that are hunted for food. Like humans, monkeys are considered disease hosts. The first human case was detected in 1970 in a nine-month-old boy during a smallpox surveillance in the Equatorial region of Zaire (today the Democratic Republic of the Congo).
Although monkeypox was detected a long time ago, not much attention was devoted to it, as it was thought that the disease didn’t have any long-term harmful effects. However, the distribution and frequency of human monkeypox have increased substantially in Central and West Africa in the last 20 years. The disease has been recognised as an increasing public health threat. Since May 2022, viral re-emergence has been observed all around the world.
Monkeypox has similarities with smallpox in terms of appearance of the symptoms and timing of the rash (occurrence and distribution). However, it is less severe than smallpox and the mortality rate is lower.
There is a need to further investigate how the virus persists in nature. How ecological and climatic factors and the interaction between the human population and the virus have an effect on the change between geographic area and the virus as a cause of disease in humans.
Transmission
It is thought that the primary animal-to-human infection happens when the virus gets into the body through broken skin, the respiratory tract and the eyes, nose and mouth. The secondary human-to-human transmission seems to occur through large respiratory droplets, direct or indirect contact with body fluids and contaminated surfaces.
According to the World Health Organization (WHO): “In the context of the current monkeypox outbreak, cases have been primarily identified among some gay, bisexual and other men who have sex with men including those who have reported recent sex with a new partner or multiple partners.
“Key transmission routes include skin-to-skin, mouth-to mouth and mouth-to-skin contact during sexual activity. Transmission can also occur through skin-to-skin contact not related to sexual practices, face-to-face contact via respiratory droplets and from contaminated surfaces or material; it is still unclear if infected people with no symptoms can transmit the monkeypox virus, making it important for anyone attending gatherings to exert additional care.”
Monkeypox in the UK
In 2018, 3 individual patients were reported as having monkeypox in the UK. Two of them had travelled to Nigeria and were symptomatic while travelling back. The other patient was a health worker.
Cases of monkeypox in England have now been confirmed again, appearing from May 2022 onwards. Individuals infected didn’t present with a history of travelling to endemic countries. By June, the number of cases in the UK had reached 846. A high proportion of these were London residents.
In Scotland, 22 cases were reported in May. By 9 September, the numbers had increased to 90 confirmed cases. As reported by Public Health Scotland: “The majority of cases are adults known to be gay, bisexual, or other men who have sex with men and report recent European travel within 21 days of symptom onset.”
Is there any protection?
Monkeypox, as mentioned above, is one of the orthopoxvirus species. It is expected, therefore, that the vaccine for smallpox should protect against monkeypox, since these viruses share genetic and antigenic (part of the virus recognised by the cells of the immune response) features. This is what we call cross-protective immunity.
Scotland is providing the Modified Vaccinia Ankara vaccine, a safer form of the smallpox vaccine, to individuals at highest risk first.
Why monkeypox now?
Although there is cross-protective immunity between the two viruses, the vaccine for smallpox was discontinued in the UK in 1971 and therefore immunity in the population has waned. The number of unvaccinated has increased, along with the increase of the frequency and distribution of the virus worldwide, and as a result we are once again hearing about monkeypox.
We are seeing more and more deforestation, civil wars, climate change, farming, refugee displacement and population movement. All of these seem to be affecting the pattern of zoonoses (infectious diseases transmitted from animals to humans) we have experienced in these last years.
Despite the fact that monkeypox is a DNA virus and doesn’t mutate as much as RNA viruses, the 2022 outbreak seems to be showing 40 mutations which distinguish it from its closest variant. Furthermore, this outbreak has been caused by multiple viral strains. These reports worry scientists and confirm the need for more research to understand how these mutations evolved.
It is time for world leaders to recognise the impact of human behaviour upon the Earth and how this is creating an increasing threat of pandemics. Pandemic preparedness must be the common first goal around the world based on universal protocols. The UK is already struggling with the effect of the previous pandemic. A large number of its population is dealing with a chronic disease (long Covid) as a consequence of not aggressively tackling the transmission.
Impact of monkeypox on public health
Will the immune response of individuals to monkeypox be the same as it has been previously in a population that can be putatively carrying another long-lasting infection? If policies don’t prioritise the basic principles of public health, such as effective quarantine, track & trace and isolation to keep transmission low, governments will be risking another ‘disaster’.
The potential impact of monkeypox disease on public health should not be underestimated, mainly when we think of the current environment for pandemic threats. At the moment, the disease can be controlled, but for how long? Two vaccines manufactured by Emergent BioSolutions and Bavarian Nordic are in short supply.
As Bernard Hoet, Bavarian Nordic vice president of medical strategy has stated, “A company like ours cannot stockpile for all the countries forever. Today we have some doses available and we are going to distribute them, but how do you want us to decide if they go here or there?” Clear proof that the UK needs to invest in bioscience, so vaccine hubs can be created, providing not only more jobs but also a rapid delivery of vaccines locally.
