The wearing of face masks and ventilation plays a major role in limiting the spread of the Covid-19 virus in public and crowded places.
However, it is within households that the virus is able to spread most effectively.
Research by scientists at Imperial College London and published in The Lancet Microbe has shown that preventing the spread of the virus within the home requires regular cleaning of surfaces and hands.
Professor Ajit Lalvani, and Director of NIHR HPRU in Respiratory Infections, explained:
“There’s no doubt that if you have COVID-19 you’re emitting the virus into the air as micro-aerosols as well as large droplets that land on your hands and the surfaces around you. What hasn’t been shown, until now, is that the presence of the virus on people’s hands or household surfaces predicts transmission to contacts.
“Our real-life study in London households provides the first empirical evidence to show that the presence of SARS-CoV-2 on people’s hands and surfaces contributes significantly to spread of COVID-19. Since we didn’t systematically sample household air, we cannot rule out airborne transmission occurring in parallel.”
After accounting for other potentially influential factors such as sex, vaccination status, underlying illnesses, and contacts’ relationship to the primary case, the researchers found that if the virus was detected on primary cases’ hands, then contacts in their household were 1.7 times more likely to get infected than those in households where primary cases did not have the virus on their hands.
Similarly, the presence of virus on primary cases’ hands was associated with a three times greater risk of contacts in the household having a positive hand-swab, and in turn, contacts with the virus on their hands were twice as likely to become infected with COVID-19.
If virus was present on frequently touched surfaces in the household, contacts were 3.8 times more likely to have detectable virus on their hands and 1.7 times more likely to be infected, i.e. to have a PCR-positive URT-swab.
Among the contacts who were initially uninfected but became infected with COVID-19 during the study, six had positive hand or household surface swabs prior to becoming infected. This supports the directionality of transmission being from household surfaces and contacts’ hands to their nose and throat.
Professor Lalvani said:
“My team’s Herculean logistical undertaking during the challenging circumstances at the height of the pandemic in real-life households strongly supports the theory that SARS-CoV-2 transmission from contaminated surfaces and hands does occur in households. With successive new variants likely to spread widely despite booster vaccinations, the simple, easily applicable public health interventions and messaging underpinned by our evidence are a valuable, risk-free and timely addition to the toolkit for living safely with COVID-19.
“Our new understanding of the pathways of household transmission now enables us to prioritise simple measures to interrupt spread of the virus. Our data strongly suggest that as well as frequent handwashing, decontamination of frequently touched surfaces could prevent transmission.”
It’s really that simple, clean surfaces and hands.
See also:
- 1,299 patients in hospital with #COVID: Slight decrease on previous week
- #Covid Related Deaths 6th April 2023
