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- A survey of 2 000 people showed those over 1.8m had a higher risk of contracting SARS-CoV-2.
- The findings support the theory that the virus is spread through aerosol transmission.
- This makes mask wearing even more critical than previously thought.
A new survey that gathered data from 2 000 people in the UK and US showed men taller than 6ft (1.8m) have double the risk of being diagnosed with SARS-CoV-2, the virus that causes Covid-19.
The research was carried out by data scientists in the UK, US and Norway, and was led by experts at the University of Oxford.
The findings don't suggest tall people are genetically more vulnerable to infection. Instead, the researchers point out that the virus could spread through aerosol transmission, which involves tiny bug-containing particles that remain suspended in the air after being exhaled.
The researchers, therefore, hypothesise that taller people are at a higher risk of being infected because they are exposed to more of these particles. The results were published in the preprint server medrxiv.org, and have yet to be peer reviewed.
Aerosol transmission of SARS-CoV-2
As the virus has been confirmed to spread via respiratory droplets, aerosol transmission has been hotly debated by scientists over the past few months. Droplets are bigger than aerosols and travel relatively short distances, whereas aerosols can accumulate in poorly ventilated areas and are carried by air currents.
The World Health Organisation (WHO) recently updated its scientific brief and conceded that aerosol Covid-19 transmission "cannot be ruled out".
"Short-range aerosol transmission, particularly in specific indoor locations, such as crowded and inadequately ventilated spaces over a prolonged period of time with infected persons, cannot be ruled out," the WHO website states.
The organisation previously ruled out the possibility that aerosol transmission of the virus was likely to occur outside a hospital setting, but after a letter, published in the journal Clinical Infectious Diseases implored public health agencies to consider this mode of transmission, their guidance changed.
Data suggests a shift
Researchers of the recent study say their findings would not have been possible if downward droplet transmission was the only transmission mechanism of SARS-CoV-2.
Of the 2 000 people surveyed, 339 people were over 1.8m.
"The results of this survey in terms of associations between height and diagnosis suggest downward droplet transmission is not the only transmission mechanism, and aerosol transmission is possible," said co-author Professor Evan Kontopantelis from The University of Manchester in a news release.
Kontopantelis added: "This has been suggested by other studies, but our method of confirmation is novel."
We should all be wearing face masks
Current non-pharmaceutical interventions to curb the spread of the virus include physical distancing of one to two metres, but this is based on the assumption that the virus is only spread via respiratory droplets, by direct contact with infected persons, or by contact with contaminated objects and surfaces.
If SARS-CoV-2 does indeed spread via aerosols, this means wearing cloth face masks is even more important in controlling the rise of infections than previously believed.
Kontopantelis explained: "Though [physical] distancing is still important because transmission by droplets is still likely to occur, it does suggest that mask-wearing may be just as, if not more, effective in prevention."
In addition to mask wearing, Kontopantelis added that air purification in interior spaces should also be further explored.
