Making sense of the ongoing monkeypox outbreak

Human-to-human spread can be effectively controlled by public health measures

The WHO has declared the ongoing global outbreak caused by the monkeypox virus (MPV), with over 16,000 cases in 75 countries, including five deaths, a public health emergency of international concern. The reason for concern: for the first time, local transmission of monkeypox is occurring in newly-affected countries without epidemiological links to countries that have previously reported monkeypox in West or Central Africa.

What is new about it?

The key takeaways from the WHO's analysis of the currently reported cases are: 99.5 per cent are males; 79 per cent of the cases are males between 18-44 years of age; few cases among 0-17 years of age; and, among those who reported their sexual orientation, 60 per cent identified as gay, bisexual and other men who have sex with men. Cases have mainly but not exclusively been identified amongst men who have sex with men (MSM) seeking care in primary care and sexual health clinics. With at least 25 reported cases among healthcare workers, there is an additional worry: are health workers getting infected through occupational exposure?

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The clinical presentation associated with the current outbreak is often at variance with the classically described clinical picture of headache, acute onset of fever (>38.5°C), swollen lymph nodes, muscle and body aches, back pain and profound weakness is absent. The WHO reports that among the cases who reported at least one symptom, 81 per cent presented with a widespread rash on the body, 50 per cent presented with fever and 41 per cent with genital rash. In many cases, the initial presentation of a genital or peri-anal rash suggests close physical contact as the likely route of transmission during sexual contact.

Is it all that 'new'?

It is now believed that simultaneous outbreaks in several non-endemic countries indicate undetected transmission for "weeks, months, or possibly a couple of years" followed by recent amplifier events. A case in point: the fourth case in India who tested positive on July 24, 2022, is reported to be a 34-year-old male residing in Delhi with no apparent history of foreign travel but with a recent history of attending a 'stag party' in Himachal Pradesh.

There are two strains of monkeypox, the West African (WA) clade with a case fatality rate of 1-3 per cent and the Congo Basin (CB) strain with a fatality of up to 10 per cent. The WA clade was imported to the United States as early as 2003 through pets. There was a multistate spread of 47 suspected cases of human infection through animal-to-human transmission, but it did not result in interhuman transmission.

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It is the predominantly urban 2017 Nigerian epidemic (also the WA clade), sustained by sporadic but regular zoonotic and interhuman transmissions, that is believed to be a game changer. By 2018, travellers returning from Nigeria had introduced the infection in Singapore, Israel and England, raising the red flag that MPV may have "emerged to occupy the ecological and immunological niche vacated by smallpox virus". A bigger worry arose when a 40-year-old female healthcare assistant in Blackpool Victoria Hospital in Lancashire, England, contracted the infection in September 2018 while cleaning the bed of a monkeypox case admitted to that hospital. With clear evidence of human-to-human transmission of the WA clade of MPV, it ceased to be a geographically limited rare disease. Other than such sporadic cases, Darklands, a fetish festival in Belgium and Gay Pride Maspalomas in The Canary Islands, attended by thousands of people – many of whom later tested positive for monkeypox in Europe and elsewhere - are now being considered super-spreader events.

What are the immediate tasks for India?

The Ministry of Health and Family Welfare released detailed guidelines on May 31 2022, and held another high-level meeting on July 24 2022, to strengthen surveillance and management across the states. The distinct features of the current outbreak need a response as that of the introduction of a new disease, just as the country responded to HIV/AIDS or Covid-19. The fact that the current phase is predominantly among MSM requires that it be approached with empathy, and utmost care is taken to avoid stigmatisation of cases and contacts. This can be understandably challenging in an outbreak situation with a high media focus; consequently, it is extremely difficult to break all chains of transmission.

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To set the ball rolling, appropriate risk communication and community engagement are crucial. The focus needs to be on raising awareness, managing risk perception, maintaining trust and proactively supporting those at risk to make informed decisions.

Clinical and public health incident response needs to be activated at district levels and a comprehensive set of activities coordinated: case finding, contact tracing, laboratory investigation, isolation, clinical management, implementation of infection prevention and control measures and vaccination activities. The frontline personnel in primary care settings need to be able to identify individuals meeting the clinical definition for a suspected case and get them tested. Implementation of appropriate infection prevention and control (IPC) measures and protecting the health workers are essential to mitigate and control transmission in health care and community settings.

All known contacts, or those suspected of being exposed, are advised to monitor their symptoms for 21 days from the last known or suspected contact and to seek a test if signs or symptoms of monkeypox manifest. Testing or quarantine are not required in the absence of symptoms. Contacts are encouraged to practice hand hygiene rigorously and respiratory etiquette, avoid contact with children or persons who are immunocompromised or pregnant and avoid any form of sexual contact for 21 days.

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The primary diagnostic test for monkeypox diagnosis is polymerase chain reaction (PCR) of skin lesions. Other specimens such as an oral, nasopharyngeal or rectal swab may also be collected, as appropriate. The Indian Council of Medical Research (ICMR) has readied 15 virus research and diagnostic laboratories (VRDL).

Monkeypox-associated risks need to be considered while planning an event now. Decision-making processes should adopt a risk-based approach tailored to the characteristics of the event under consideration. At the same time, there should not be a blanket cancellation of postponing or cancelling gatherings in areas reporting monkeypox cases; rather, gatherings should be used as opportunities for information dissemination and community engagement.

On vaccines

Stockpiles of smallpox vaccines constitute first-generation vaccines for monkeypox but are not recommended as they do not meet current safety and manufacturing standards.

Second and third-generation safer vaccines for smallpox may be relevant for monkeypox and are approved for the prevention of monkeypox. The supply of these vaccines is limited, and the national technical advisory groups have been called upon to take appropriate decisions. There is no role of mass vaccination at this time. Pre-exposure vaccination is recommended for health workers at high risk of exposure, including laboratory personnel working with orthopoxviruses, those performing diagnostic testing and outbreak response team members as may be designated by national public health authorities.

Post-script

Much like the early phases of HIV/AIDS, this is an unfolding outbreak and modes of transmission are not yet fully understood. While human-to-human transmission requires prolonged face-to-face contact in close proximity or skin-to-skin physical contact, such exposure can occur in diverse settings, including at home, in social or sexual networks or the health care setting. The current priority is to put in place a robust surveillance and containment strategy.

(The writer is Chairperson at the Centre of Social Medicine & Community Health, Jawaharlal Nehru University, New Delhi)

Disclaimer: The views expressed above are the author's own. They do not necessarily reflect the views of DH.