There are more than 4,100 confirmed cases worldwide, including at least 13 in Australia.
Sydney:
The World Health Organization (WHO) has decided not to declare monkeypox a public health emergency of international importance. This may change in the future.
However, WHO Director-General Tedros Adanom Gebrejesus said he was “deeply concerned” about the growing threat of monkeypox, which he said had reached more than 50 countries.
There are more than 4,100 confirmed cases worldwide, including at least 13 in Australia.
The WHO also acknowledged that there were many unknowns about the outbreak.
Here are three things we know about monkeypox and three things we want to understand.
3 things we know
1. Monkeypox is caused by a virus
Monkeypox is a large DNA virus belonging to the orthopoxvirus family. Unlike the associated smallpox virus, smallpox, which affects only humans, the monkeypox virus is found in rodents and other animals in parts of Africa.
We know of two clusters (viral groups) and this is the less severe of the two currently circulating outside Africa.
Orthopoxviruses are stable viruses that do not mutate much. However, many mutations have been described in the virus that causes the current epidemic.
At least two separate strains are circulating in the United States, suggesting repeated introduction into the country.
2. You may be infected for more than a week and not know it
It takes an average of 8.5 days from infection to the onset of symptoms such as swollen lymph nodes, fever and a rash that usually looks like fluid-filled blisters that erupt. People are contagious while they have a rash, and are usually infectious for about two weeks.
Children are most severely affected and have a higher risk of death from the disease. Historically, in endemic countries in Africa, almost all deaths were children.
The European epidemic is predominantly among older men, so this, together with better access to care, may explain the low mortality rate in these countries.
3. We have vaccines and treatments
Vaccines work. Previous smallpox vaccination provides 85% protection against monkeypox. Smallpox was declared eradicated in 1980, so most mass vaccination programs were discontinued in the 1970s.
Australia has never had a mass vaccination against smallpox. However, about 10% of Australians have been vaccinated in the past, mostly migrants.
Vaccines protect for many years, but immunity decreases. So declining protection at the population level is probably responsible for the resurgence of monkeypox observed since 2017 in Nigeria, one of seven endemic hotspots in Africa.
Mass vaccination is not recommended. However, vaccines can be given in contact with confirmed cases (known as post-exposure prophylaxis) and people at high risk of contracting the virus, such as some laboratory or healthcare workers (before prophylactic prophylaxis).
There are also treatments such as immunoglobulin against vaccines and antivirals. They are designed against smallpox.
3 things we want to understand
1. How important are these new mutations?
The virus causing the current epidemic has several mutations compared to the versions of the virus circulating in Africa. However, we do not know whether these mutations affect the clinical disease and how the virus spreads.
The monkeypox virus has a very large genome, so it is more complex to study than smaller RNA viruses, such as influenza and SARS-CoV-2 (the virus that causes COVID).
Experts wonder if the mutations have made it more contagious or changed the clinical pattern to make it look more like a sexually transmitted infection. A study from Portugal shows that mutations are likely to make the virus more transmissible.
2. How is it spread? Is that changing?
In the past, monkeypox was not described as a sexually transmitted infection. However, the current transmission model is unusual. There seems to be a very short incubation period (24 hours) after sexual intercourse in some, but not all, cases.
It is a respiratory virus, so aerosol transmission is possible. But historically, most shows have been from animal to human. When there was transmission between people, it usually involved close contacts.
However, the rapid growth of the epidemic in non-endemic countries in 2022 is entirely due to the spread among people. There may be many more cases than officially reported.
We do not know why the pattern has changed, whether it is sexually transmitted or simply transmitted through intimate contact on specific and globally connected social networks, or the virus has become more contagious.
The virus is found in skin rashes, mouth and semen, but this does not prove that it is sexually transmitted.
3. How far will it spread? Does COVID make a difference?
Will this spread more widely in society? Does the COVID pandemic increase the risk? Probably yes.
Nor should we drop the ball on surveillance in the wider community or condemn the LGBTQI community.
Due to the weakening immunity of the smallpox vaccine worldwide and the spread of monkeypox in many countries, we can now see that the epidemic is spreading more widely.
If this happens and starts infecting a large number of children, we could see more deaths because the children get a more severe infection.
So we need to watch worldwide for clusters of fever and rash and misdiagnosis such as chickenpox, foot-and-mouth disease, herpes simplex or other diseases with a rash.
Another factor is COVID. While people are recovering from COVID, their immune system is compromised. So people who have had COVID may be more susceptible to other infections.
We see the same thing with measles. This weakens the immune system and increases the risk of other infections for two to three years thereafter.
If the epidemic settles in countries outside endemic areas, it could infect animals and create new endemic areas around the world.
It is important that we do everything we can to stop this epidemic.
C Raina MacIntyre, Professor of Global Biosafety, Principal Research Fellow, NHMRC, Head, Biosafety Program, Kirby Institute, UNSW Sydney
This article is republished by The Conversation under a Creative Commons license. Read the original article.
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