Can Mpox virus spread through air like Covid-19?

New Delhi: Respiratory droplets might play a role in the spread of Mpox but not as efficiently as Covid-19 or even flu, said infectious disease experts on Wednesday.

Mpox is a viral zoonotic disease that occurs primarily in tropical rainforest areas of central and west Africa and is occasionally exported to other regions. The disease is currently seeing an outbreak in Africa with over 14,000 cases and 524 deaths have been reported, and the World Health Organization (WHO) has declared it a global health emergency.

It majorly causes fevers, headaches, and muscle aches, as well as painful boils on the skin. It spreads from person to person through close, skin-to-skin contact.

According to the US Centers for Disease Control and Prevention (CDC), prolonged face-to-face interactions (such as talking or breathing)” may increase the risk of transmission. The WHO also maintains that respiratory droplets (and possibly short-range aerosols) can result in Mpox transmission.

“This suggests that respiratory droplets might play a role in transmission. That being said, it's considered to play a lesser role in transmission dynamics as compared to direct intimate contact and sexual contact which are the primary modes of transmission,” Dr. Dipu T S, Professor and Unit Chief, Infectious Diseases Department, Amrita Hospital, Kochim told IANS.

A recent study published by the University of New South Wales in Australia showed that the current outbreak caused by the Clade 1 strain has reported 70 per cent of cases and 88 per cent of deaths in children in the Democratic Republic of Congo (DRC).

“The predominance of children in the DRC epidemic suggests transmission may be respiratory. In fact, smallpox and Mpox are respiratory viruses, and Mpox has been identified in ambient air,” the researchers noted.

The study showed that the variola virus (smallpox) was highly airborne, “with the potential to transmit over long distances”.

Another study by a team of Spanish researchers in a 2023 study published in the journal The Lancet Microbe also showed that Mpox raised the risk of transmission indoors in poorly ventilated rooms.

Referring to the US CDC, Dr. Lancelot Mark Pinto, Consultant Pulmonologist and Epidemiologist, P. D. Hinduja Hospital & Medical Research Centre, said that the keywords are “prolonged” and “face-to-face”.

“Unlike highly transmissible airborne viruses such as influenza and SARS-CoV-2, Mpox isn’t likely to spread during casual short encounters,” Pinto told IANS.

“Family transmission, sexual partner transmission, and caregiver transmission is much more likely, and therefore such encounters would need added protection,” he added.

The 2022-2023 global outbreak of Mpox was caused by a strain known as clade IIb. Since 2022, the WHO has reported 99,176 cases and 208 deaths due to monkeypox from 116 countries.

A total of 30 cases were detected in India, with the last case in March 2024.

Global scientists claim that if the more pathogenic Clade I Mpox becomes highly transmissible between humans, it may pose a greater pandemic threat than Clade IIb.

However, Hans Kluge, WHO regional director for Europe, in a recent media briefing stated that Mpox, regardless of Clade IIb or Clade Ib, is not the new Covid, as speculated. He said health authorities know how to control its spread.

Currently, there is no proven treatment against Mpox.

Bavarian Nordic’s MVA-BN vaccine (Jynneos/Imvanex) -- approved in the US, Europe, and Canada -- is the leading Mpox vaccine worldwide.

In addition, KM Biologics’ LC16 vaccine is available in Japan and Emergent BioSolutions’ ACAM2000 is also under regulatory review for Mpox in the US.

The Serum Institute of India (SII), the world's largest vaccine maker, has also announced plans to develop a vaccine for Mpox.

“Serum Institute of India is currently working on developing a vaccine for Mpox,” said CEO Adar Poonawalla, in a statement, adding that the company will share “positive news within a year's time”.

“To prevent the transmission of Mpox, the general public should avoid close contact with infected individuals, and practise good hygiene by regularly washing hands and disinfecting surfaces,” Dipu told IANS.