June 14, 2024

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Nose-Picking Health Workers Had Higher COVID Risk

Surveyed hospital workers who admitted to picking their nose were three to four times more likely to wind up having a COVID infection, and the prevalent habit may be an underrecognized source of spread, Dutch researchers suggested.

Early on in the pandemic, COVID incidence was significantly greater among respondents who reported picking their nose at least incidentally, and with some degree of regularity, compared with those who refrained at all costs (17.3% vs 5.9%; adjusted OR 3.80, 95% CI 1.05-24.52), reported Jonne Sikkens, MD, MSc, of Amsterdam Institute for Infection and Immunity in the Netherlands, and colleagues.

Writing in PLoS ONE, they suggested that “perhaps the role of nose picking is underestimated” when it comes to SARS-CoV-2 transmission among hospital staff.

“The viral load in the nasal mucosa is high in the days after contracting a SARS-CoV-2 infection, even before the onset of symptoms and in patients that remain asymptomatic,” they noted. “Nose picking HCW [healthcare workers] who are infected with SARS-CoV-2 could contaminate the work environment, potentially leading to further transmission.”

Workers at Amsterdam University Medical Centers were retrospectively surveyed in December 2021 about their behaviors during the first and second waves of the pandemic, with 85% of the Dutch cohort owning up to picking their nose either daily, weekly, or monthly. Responses were matched against prospectively collected SARS-CoV-2 test results at the hospitals from March through October 2020.

A noted limitation of the study was that “the depth of penetration and eating of boogers” among the nose pickers was not evaluated, said Sikkens and colleagues.

Nose pickers tended to be younger (mean age 44 vs 53 years for non-pickers) and were more likely to be men (90% vs 83%), with doctors being the worst offenders.

While COVID prevention guidelines suggest personal protective equipment (PPE) for workers dealing with patients and offer strict hand hygiene protocols, nose-picking doesn’t make the cut. But it should, said Sikkens and co-authors.

“Nose picking deserves more consideration as a potential health hazard, and explicit recommendations against nose picking should be included in the same SARS-CoV-2 infection prevention guidelines,” they wrote.

The findings, said Sikkens and colleagues, highlight how critical the nasal cavity is when it comes to SARS-CoV-2 transmission, as “nose picking may facilitate viral entry by directly introducing virus particles present on the hands to the nose, thus facilitating infection.”

Researchers also examined other behavioral habits like nail biting, wearing glasses, and having a beard, with adjustments for all made for COVID exposure, though none of these were associated with an increased risk of infection.

Concern around glasses and beards involves the potential for less-than-ideal fitting PPE, though glasses, if anything, seemed potentially protective in the study (OR 0.49, 95% CI 0.23-1.06); prior studies have shown conflicting results as to whether eyewear confers protection against infection.

Given the study timeframe and the rash of COVID preprints unleashed during the pandemic, why did researchers only now release these findings? In part because the cohort evaluated yielded large amounts of data and priorities needed to be made, Sikkens told MedPage Today.

“We did prioritize the analyses based on research subjects that were thought to be most urgent, leading to our earlier publications for instance on vaccine response and infections in healthcare workers,” he said by email. “The current data would have been useful to have earlier in the pandemic, but others were thought to be even more important.”

For their study, the team sent out surveys to 404 healthcare workers at the Amsterdam University Medical Centers in December 2021, with 52% of the workers responding.

Of the 219 respondents, three-fourths were women. Most respondents were nurses (45%) or support staff (35%), with doctors (15% specialists, 5% residents) rounding out the rest of the cohort. Residents and specialists (100% and 91%, respectively) were the most frequent nose pickers, followed by support staff (86%) and nurses (80%).

Frequency of nose picking did not appear to be linked with any difference in COVID infection risk, with positive cases in 27% of those who reported monthly picking, 35% among weekly pickers, and 32% of daily pickers. No participants reported picking their nose every hour, thankfully.

One-third of the cohort reported nail biting, two-thirds wore glasses, and 31% of the men had beards.

A study strength was that SARS-CoV-2 positivity was determined by prospective longitudinal serological sampling, though this was all done pre-Omicron and pre-vaccine availability and therefore might not be generalizable to the current circulating variants or to the vaccine era. Another limitation involved the survey timing — as it was conducted retrospectively, it may have introduced recall bias.

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    Ian Ingram is Managing Editor at MedPage Today and helps cover oncology for the site.


The study was funded by the Netherlands Organization for Health Research and Development ZonMw and the Corona Research Fund Amsterdam UMC.

Sikkens and co-authors declared having no competing interests.

Primary Source


Source Reference: Lavell AHA, et al “Why not to pick your nose: Association between nose picking and SARS-CoV-2 incidence, a cohort study in hospital health care workers” PLoS ONE 2023; DOI: 10.1371/journal.pone.0288352.