A study among health care workers in the Netherlands has shown that those who are habitual nose-pickers were more likely to contract COVID-19. On the other hand, beard wearers and glasses wearers were no more likely to contract the disease.
The research investigated whether certain behavioural and physical features, e.g. nose picking and wearing glasses, are associated with infection risk. In a study among 404 healthcare workers in two university medical centres in the Netherlands, SARS-CoV-2-specific antibodies were measured during the first phase of the pandemic. A survey was subsequently carried out regarding behavioural (e.g. nose picking) and physical features.
The end of 2019 marked the beginning of the global SARS-CoV-2 pandemic. Worldwide, preventive measurements were introduced aiming to reduce physical contact, and droplet and aerosol transmission. In healthcare facilities, guidelines recommended the use of personal protective equipment (PPE) for those working in direct patient care, including the use of facemasks, a gown and goggles/face shields, as well as gloves and strict hand hygiene protocols. Little did we know that there was another source of infection lurking behind the statistics – nose picking.
Hygiene
The study was prompted by findings that despite PPE guidelines, health care workers working with COVID patients are more likely to contract infections compared with those not working in patient care. Risk factors include poor implementation of hand washing hygiene and use of PPE. The main route of infection is via the nose, but it was unknown whether transmission of the COVID virus was affected by habitual hand-nose contact, as occurs in nose picking and nail biting.
Studies suggested that a large proportion of the adult population regularly pick their nose, and it is suggested that regular nose picking and nail biting in an environment with high levels of circulating virus enables the virus’s transfer to the nasal or oral mucosa. Infection risk may be further increased when mucosa are damaged, e.g. from the strain due to ‘repetitive nasal finger penetration’. Also, it is unknown whether transmission risk is affected by physical features influencing fit of PPE and susceptibility to droplets, for example having a beard or wearing glasses. The latter is of interest since the liquid coated membranes in the eye have been identified as another possible route of SARS-CoV-2 transmission.
The majority of healthcare worker surveyed (84.5%) reported picking their nose at least incidentally, with frequency varying between monthly, weekly and daily. COVID-19 incidence was found to be higher in nose pickers compared to participants who refrained from nose picking (17.3% vs. 5.9%). No association was observed between nail biting, wearing glasses, or having a beard, and the incidence of infection.
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Features
A total of 219 workers completed the survey regarding behavioural and physical features of interest. Habitual nose picking, varying from monthly, weekly to daily, was disclosed by 185 (85%) respondents. Nose pickers were younger than non-nose pickers (median age in years for nose pickers 44) and for non-nose pickers 53, and males reported more frequently nose picking (90%) compared with females (83%). Doctors were the most frequent nose pickers (residents: 100% and specialists: 91%), followed by support staff (86%) and nurses (80%).
Nail biting (monthly, weekly, daily or hourly) was less frequently reported (33%), 158 (72%) participants reported wearing glasses and 18/52 males (35%) reported having a beard. By October 2020, which was the start of the second pandemic wave in the Netherlands, 34/219 (16%) surveyed were SARS-CoV-2 positive. Only 2 (6%) of these seropositive participants never picked their nose, while 9 (27%) reported monthly nose picking, 12 (35%) weekly and 11 (32%) daily.
There was no significant association found between nail biting and the incidence of SARS-CoV-2 infection. Glasses-wearing respondents contracted SARS-CoV-2 infection at a lower rate compared to those without glasses, but the difference was not significant.
