Link between spitting and disease transmission is overstated: Professor Ross Coomber
The government has banned spitting in public places and it is now a punishable offence under the Disaster Management Act, 2005, in a bid to prevent the spread of coronavirus disease (Covid-19), which transmits through respiratory droplets released from nose and mouth.
Spitting has been associated with spreading disease, particularly tuberculosis (TB), for over a century. In 1896, New York City passed the first anti-spitting legislation based on public health grounds.
More recently, in 2011, a councillor in London said “banning spitting (in the borough of) Enfield will help combat TB, which has been on the increase in London”.
Lately, it has been linked with the spread of HIV that causes AIDS, hepatitis B&C that cause jaundice and liver damage, or herpes, with hundreds of cases worldwide where prosecution for assault was brought, or partially so, on this basis.
Several states such as Delhi, Goa, Bihar, Jharkhand, Telangana, Uttar Pradesh, Uttarakhand, Maharashtra, Haryana, Nagaland and Assam, and cities like Mumbai have banned smokeless chewing tobacco like paan and gutka, and spitting in public places, with some introducing the ban to stop the spread of Covid-19.
But does spitting really spread disease? Professor Ross Coomber, the head of department of sociology, social policy and criminology, University of Liverpool, the United Kingdom (UK), who has extensively studied spitting practices in Asia, including both India and China, believes that the promulgated public health risks are commonly exaggerated, relatively unproven and promote what in reality is a public nuisance but has become a public health hazard.
Why do people spit? Is it a habit particular to Asia, or is it also prevalent in other regions of the world?
Spitting varies in prevalence around the world, but historically it was extremely prevalent in most countries. The Asian region does appear to be where the greater levels of prevalence occur, as a region. People spit for many reasons but the normal reasons -- divorced from customs or a particular culture, sealing contracts, showing determination in sport, showing contempt, warding off evil, etc; -- would be to clear their throats/lungs in the same way that many people blow into their handkerchiefs in the West or to do so habitually.
How are spitting behaviours different in India, than, say, China?
In India, I observed two primary types - habitual ‘functional’ spitting by men and women, young and old who ‘just spat’ often not forcefully but just ridding of saliva but also spitting related to the widely-used chewed paan and gutka, which is a heady mix of cultural activities, fashion, need (if choosing not to swallow), and tradition.
In China, it was almost exclusively functional but also louder and more forceful. Arguably, the everyday spitting in both countries is mostly accepted and largely unseen except by those that oppose it.
In South Korea, it was almost exclusively combined with smoking and smokers would often draw on a cigarette, inhale and then spit.
Does spitting spread disease? What do research studies say?
Current research evidence shows that saliva, and thus spittle, although capable of containing viruses and other pathogens, is not considered a bodily fluid through which diseases such as HIV, hepatitis A, B and C are transmitted largely due to the low-level that pathogens are found in saliva. There is almost no evidence to show that public spitting is, in reality, a significant contributor to disease or virus spread as opposed to the assumption that it is because saliva can contain disease/or viruses.
In terms of a hierarchy of risk for the transmission of TB, the disease most commonly associated with spitting, the strongest evidence for transmission, however, is elsewhere. As far as the available research suggests, direct close-range coughing or breathing; hand-to-hand touching; kissing (although even mouth-to-mouth resuscitation carries low risk); directly touching pathogen-contaminated surfaces such as handrails, doorknobs and so on; and close living and/or working with others in poorly ventilated rooms carry the most significant transmission risks.
Are there any estimates for how many people spit? Has the subject been studied enough?
Studies on spitting -- even epidemiological studies -- are rare/thin on the ground. Yes, more systematic studies would be helpful. There are only anecdotal estimates of people spitting and I think there is some Chinese reporting on counting from before the Olympics were held there.
I would argue and the evidence suggests (in relation to TB, at least, as the size and virulence of transmittable pathogens vary between diseases) that the link between spitting and disease transmission is historically exaggerated and overstated, particularly with spitting downwards to the ground and is as much a morally/civility based concern as it is a health issue. The campaigns against spitting have a long history of being as much driven by morality as health. A zero-risk approach, of course, would suggest not spitting or sneezing or coughing or even breathing directly in the vicinity of others.
The Sars-Cov-2 virus that causes Covid-19 is found in throat swabs and spreads through droplets. Do you believe stopping spitting will stop its spread?
Social distancing and sensible all-round behaviour (washing hands etc.) are probably the most important. It seems sensible to suggest that not forcefully projecting bodily fluids into the air should be behaviour but I would suggest that spitting to the ground is not the same as spitting into the air, which happens rarely. It is probably best and sensible to stop all projectile bodily emissions in the current context, whenever possible.
How difficult is it for people to change behaviours and stop after a lifetime of spitting?
I would suggest it will be very difficult for some but not all. We are all being asked to change our behaviours in many ways. It might be more difficult for those that regularly or even compulsively chew paan or gutka that contain nicotine, tobacco and other addictive substances, such as stimulants. There will a desire and need to chew those substances that will be toughest to break and the spitting will then follow that continued behaviour.