By Carlos Manuel Eusoya

In late 2021, the World Health Organization (WHO) declared that the SARS-CoV-2 virus, popularly known as COVID-19, is airborne. The announcement was made two years after the onset of the pandemic. As the looming threat of monkeypox begins its spread in European and North American nations, is there a definitive answer whether this viral disease is airborne?

Photos courtesy of Medic India and India Times

The short answer is no. But the science behind it is a little more complicated.

Monkeypox, which likely originated from the African continent, was recently declared by WHO as a global emergency due to the number of international cases rising to 17,000. The primary symptoms of this viral disease includes fever, back pain, headaches, and muscle aches; infected patients may later observe rashes and swollen glands on their skin, most specifically in their limbs, face, and on the cornea portion of their eyes.

As per the original reports and findings of WHO and the Center for Disease Prevention and Control (CDC), there were two major modes of transmission for the virus; the first being animal-to-human transmission (such as contact with blood or fluids of infected monkey carriers). The second and more common pathway is human-to-human, which may be transmitted through coughing, sneezing, and objects contaminated with these cough droplets.

Recent findings suggest there could be another pathway for infection: the air.

Why Monkeypox may be airborne

Scientists have established the fact that monkeypox is closely related to its more common counterpart — smallpox. There have been various studies citing the possibility of airborne transmission for smallpox viruses.

For example, a news report published in National Center for Biotechnology Information (NCBI), discussed the smallpox outbreak that occurred in New York City last 1947, and revealed that one infected patient in a hospital infected another patient housed seven floors away from him. The most plausible possibility is that the virus was transmitted through air currents in the hospital infrastructure.

This finding was further supported by a smallpox outbreak that occurred in a Nigerian prison last 2017, when two health workers were infected with the smallpox virus, even though they never directly touched or approached the patient inside the prison building; as well as in a German infection case in 1970, where a “patient zero” spread the virus towards other hospital patients and workers floors away from him.

“Most people think that smallpox usually is transmitted by large droplets, but it can, for whatever reason, occasionally be transmitted by small-particle aerosols,” stated virologist Mark Challberg.

Why Monkeypox may NOT be airborne

While there is a strong case for the airborne transmission of monkeypox, there are some rebuttals from the scientific community. One of which is the fact that there are still differences in the structures and symptoms between smallpox and monkeypox. 

Monkeypox is relatively milder than its smallpox, which may indicate a possibility that the monkeypox virus cannot be transmitted via air as easily as its latter counterpart. As the CDC notes, monkeypox is “less contagious”.

Another argument says that monkeypox is not originally airborne due to its genomic structure; it was only later on that mutations caused the virus to gain airborne transmission. Syracuse University Brittany Kmush quoted that “Typically, monkeypox is not thought of as an airborne virus… but its mode of transmission may have changed and subsequently, caused this outbreak.”

So… how would we know if monkeypox is an airborne disease?

More studies are needed to confirm the possibility of airborne transmission for the monkeypox virus, as well as the mechanism for the airborne infection, if there is any. “It’s very ambiguous what the true or dominant route of transmission is, and some of that can be addressed in animal models… [it] needs to take a front seat for some of the laboratory research,” quoted Nancy Sullivan, a researcher at the National Institute of Allergy and Infectious Diseases.

For now, the CDC recommends avoiding direct contact with known patients, as well as isolation for individuals infected with monkeypox. The use of face masks in preventing monkeypox is still an issue for debate.