Mpox (also known as monkeypox)

What is Mpox?

Mpox (also known as monkeypox) is a zoonosis caused by Mpox virus. The virus was first discovered in 1958 in monkeys. The first case in humans was reported in 1970 in the Democratic Republic of Congo (then known as Zaire), since then human cases have mainly been reported in West and Central African countries: Benin, Cameroon, the Central African Republic, the Democratic Republic of the Congo, Gabon, Cote d’Ivoire, Liberia, Nigeria, the Republic of the Congo, Sierra Leone and South Sudan.

The incubation period is usually from 6 to 13 days, with a range from 5 to 21 days. The symptoms are similar to Smallpox, but in milder forms. Initial symptoms include fever, intense headache, myalgia and lymphadenopathy. Severe swollen lymph nodes before the appearance of rash could be a distinctive feature. Lesions in mouth and body appear about 1 to 3 days after onset of fever, then progress from maculopapules to vesicles, pustules and followed by crusts within a period of 10 to 14 days. Lesions typically progress simultaneously at all parts of the body.

Mpox is usually a self-limited disease with symptoms lasting from 14 to 21 days. The case fatality in previous outbreaks has been between 1% (West African strain) to 10% (Congo strain).

How does it spread?

Animal-to-human transmission can occur via direct contact with the blood, body fluids, or lesions of infected animals including squirrels, Gambian pouched rats, dormice, and different species of monkeys.

Human-to-human transmission is also possible through respiratory droplets during prolonged face-to-face contact or direct contact with skin lesions, body fluids or recently contaminated objects. Transmission can also occur via the placenta from mother to fetus.

How can you prevent it?

The Government has procured a third generation vaccine called "JYNNEOS" by making reference to the earlier recommendations of the Scientific Committee on Vaccine Preventable Diseases and the Scientific Committee on Emerging and Zoonotic Diseases as pre-exposure and post-exposure vaccination. The vaccine has arrived in Hong Kong in September 2022 to be used in the Mpox Vaccination Programme. "JYNNEOS" has been licensed by the U.S. Food and Drug Administration (FDA) for the protection of mpox in 2019.

To reduce the risk of infection, members of the public travelling to places affected by monkeypox virus should:

• Avoid close, skin-to-skin contact with sick people or people with a rash that looks like mpox;
• Avoid contact with objects and materials that a person with mpox has used, such as eating utensils or cups, bedding, towels, or clothing;
• Avoid contact with sick or dead animals;
• Implement appropriate infection control precautions when taking care of ill people or handling animals, such as wearing protective clothing and equipment including gloves and surgical masks;
• Maintain hand hygiene. Clean hands with liquid soap and water when they are visibly soiled or likely contaminated with blood and body fluid. When hands are not visibly soiled, they could be cleaned with 70-80% alcohol-based handrub;
• Thoroughly cook all animal products before eating; and
• Seek medical advice promptly for any suspicious symptoms.

How is it treated?

In principle, treatment of mpox includes the control of symptoms, management of complications and the prevention of long-term sequelae. Secondary bacterial infections should be treated as indicated. An antiviral agent known as tecovirimat that was licensed by the European Medicines Agency for mpox in 2022, but it is not yet widely available.

For more information on Mpox, including the latest situation in overseas countries or places, please visit the World Health Organization and Centre for Health Protection’s thematic webpages at:
https://www.who.int/news-room/fact-sheets/detail/monkeypox
https://www.chp.gov.hk/en/features/105683.html