MONKEYPOX belongs to the genus Orthopoxvirus and is related to the variola virus that causes smallpox. Thus, smallpox vaccines also prevent monkeypox.
It has an incubation period of 5-21 days and spreads when symptoms are present. It remains contagious until the skin lesions scab over and heal (2-3 weeks). It is a zoonotic infection with person-to-person transmission, sometimes through close contact. In West Africa, most cases were in children.
Prior to this outbreak, the clinical picture was described as fever, malaise and lymphadenopathy, with the rash first appearing in the mouth. In most cases, there is a rash on the face and lymphadenopathy, followed by a rash on the palms and soles, and in 30% of cases there is a rash on the body and genitals.
Monkeypox is usually a self-limiting disease with symptoms lasting 2 to 4 weeks. However, complications can occur, especially in children and immunocompromised individuals, including eye infections, blindness, skin infections, sepsis, encephalitis, and pneumonia. In Africa, the West African clade has a mortality rate of 3.6%, compared to 10.6% in the Congo Basin clade.
After small outbreaks of zoonotic diseases between 1970 and 2016, with imports to the United Kingdom, Singapore and Israel, much larger epidemics began in Nigeria and the Democratic Republic of the Congo in 2017.
The smallpox vaccine is 85% effective in the primary prevention of monkeypox. In the 42 years since eradication, the number of people without vaccination has increased, and immunity to vaccines is declining in the elderly. The resurgence of monkeypox in Nigeria can be attributed to the loss of immunity to smallpox.
We may be more vulnerable because Australia has never had mass vaccination. Only 10% of Australians (mostly expatriates) have been vaccinated, and today around one in five people live with drug-induced immunosuppression. From a blood sample from a donor in New South Wales, we estimated near-zero immunity to the vaccine in Australia.
As of June 27, 2022, there have been 13 cases in Australia (in New South Wales and Victoria), more than 1,700 cases from seven African countries, mostly children, and over 4,000 from more than 30 countries since May 13. More cases have been reported. outside the African continent. More than half of these were adult males from the UK, Portugal and Spain, while the remainder were mostly males from Europe and North America.
This is the first ongoing transmission from the community outside the African continent. Almost all cases in Europe do not have a travel history to endemic countries, but have a history of travel within Europe to or from Europe. To date, more than 99% of cases are in men who have sex with men, although transmission to healthcare workers has been documented (here and here). The clinical picture is different: the lesions often start in the genital area rather than the face. Hospitalization was rare and there were no deaths. The epidemic is associated with a West African group with several new mutations. There is a possibility of transmission through skin-to-skin contact during sexual contact or other close contact.
Epidemic diagnosis, treatment and control
Diagnosis can be made by polymerase chain reaction (PCR) or by nucleotide sequencing of a clinical sample. Clinical and epidemiological criteria can be used to determine probable or suspected cases. Effective antivirals include tecovirimat and brincidofovir. You can also use cidofovir, but it is nephrotoxic. Vaccinia immunoglobulin is effective, but supplies are limited. Epidemic control includes case detection, case isolation, contact tracing and ring vaccination. Contact exposure is classified according to the type of exposure and individual exposure.
Smallpox vaccines can be given to frontline health workers and laboratory workers or as post-exposure prophylaxis (PEP) for close contact (so-called \”ring vaccination\”). Vaccines used in the form of PEP are most effective within 4 days of exposure, so contact tracing is essential. Currently, mass vaccination is not justified.
The risk/benefit balance of the PEP vaccine should take into account the local epidemiology, as well as the risks associated with the available vaccines. First and second generation smallpox vaccines contain live vaccinia virus and are contraindicated in immunocompromised people because of the risk of fatal disseminated vaccinia infection. Other serious side effects are myocarditis and vaccinated eczema. Third generation vaccines are unable to replicate and can be safely administered to immunized people. Human immunodeficiency virus (HIV) co-infection was found in 14 out of 27 cases in Portugal. Immune deficiencies, including those associated with progressive HIV
-Infection is associated with a more severe course of the disease.
What is Australia to do?
The goal is to prevent human outbreaks and the spread of monkeypox to animal hosts in Australia. The introduction of dengue fever in Australia and now Japanese encephalitis are lessons worth noting. active
Need for monitoring and control
ial, ideally for immediate use with antivirals for close contact and with third-generation smallpox vaccines. If second-generation vaccines are used, antivirals should be readily available to treat disseminated vaccinia.
Gay, bisexual and other men who have sex with men who have recently returned from abroad, especially from Europe, should be monitored for symptoms and, if they are concerned, visit their GP or local sexual health clinic. Australian LGBTQ health organizations with roots in the fight against HIV are central to an effective prevention response. They have already issued an alert informing the community members about the mode of transmission, the need for medical attention and isolation of those with signs and symptoms. Community-led initiatives like these are crucial to instilling confidence in the response. Monkeypox is probably not limited to men who have sex with men. Stigmatization of people with monkeypox and those at high risk should be avoided, as this can lead to fewer tests and reduced participation in health counseling.
Are we ready?
The Australian health system can respond effectively to monkeypox, especially if we procure third-generation vaccines and antiviral drugs quickly and use them actively to fight the pandemic. We have a good surveillance system and on June 1, 2022, monkeypox became a nationally notable disease.
Australia has made tremendous progress in the fight against HIV and can use this infrastructure, community groups and expertise, and infrastructure to fight the coronavirus disease 2019 (COVID-19). However, if the monkeypox epidemic becomes widespread in Australia, the continued burden of COVID-19 on the health system could become a problem. Fatigue from the COVID-19 pandemic could also mean that people are less likely to follow health advice.
Vaccination of close contacts should be the first step. Given the high incidence of cases among men who have sex with men, if cases rise, we may need to consider giving the vaccine to men who have sex with men who have multiple partners. as currently in Montreal, Canada. Finally, the pandemic occurred during a period of transition from one government to another, so promptness and good communication are important. We have the experience, resources and tools to respond quickly and successfully.
is monkeypox dangerous