Dentists in Germany not more likely to catch COVID-19

Jeremy Booth, Dental Tribune International

Mon. 7. February 2022

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GREIFSWALD, Germany: A study by researchers at University Medicine Greifswald compared the risk of SARS-CoV-2 transmission among dental teams with that of the general population and aimed to clarify the impact of protective measures in dental settings. The study, specific to Germany, found that dental professionals in the country faced no elevated occupational risk.

At the beginning of the pandemic, it was assumed that dentists and their teams were more susceptible to SARS-CoV-2 infection, owing to their close contact with patients and the use of aerosol-generating procedures (AGPs) in their work. In the ensuing months, as scientists learned more about the virus, different studies either supported or disputed this hypothesis.

In light of the uncertainties surrounding the risk of transmission in dental settings—and because no Germany-specific study had been undertaken—the researchers conducted a cross-sectional study of 2,784 dental professionals from around 1,125 clinics in Germany. The research was undertaken between January and April 2020 in five regions of the country which had been found by the Robert Koch Institute (RKI) to have a high incidence of SARS-CoV-2. These were Dresden, Berlin, Hamburg, Cologne/Düsseldorf and Stuttgart.

Each participant returned a dry blood collection set that was then tested for anti-SARS-CoV-2 IgG antibodies, and they each completed a questionnaire. The questionnaire asked participants whether they had had a previous SARS-CoV-2 infection confirmed by a PCR test, what their vaccination status was and whether they had treated patients who had tested positive for the virus. The researchers considered participants as having been infected with the virus if they showed SARS-CoV-2 antibodies, or if they self-reported a positive PCR test. The control population was selected from a nationwide population sample.

“Probably, the widespread use of FFP masks, ventilation measures, and the low virus load in the [AGPs] contributed to these findings”

Of the participants, 146 tested positive for SARS-CoV-2 antibodies, and self-reporting of infection brought the total to 179, or 6.5% of the sample. The frequency of antibodies was found to be highest in Dresden (8.2%) and Stuttgart (5.0%), followed by Cologne/Düsseldorf (4.8%), Berlin (3.3%) and Hamburg (1.9%). The researchers wrote: “In the general population, the cumulative incidence of PCR-validated SARS-CoV-2 infections reported to the RKI for the time between October 1, 2020, and April 15, 2021, was 5.0% for Dresden, 4.1% for Berlin, 3.4% for Hamburg, 3.7% for Cologne, and 3.5% for Stuttgart.”

Based on these results, the researchers concluded that dentists and dental teams in Germany had not faced an increased risk of patient–dentist transmission. “Our tentative conclusion is composed of our results as well as information from the reported literature. Probably, the widespread use of FFP masks, ventilation measures, and the low virus load in the [AGPs] contributed to these findings,” they wrote.

The researchers cited two studies by the RKI which had found that, between January and March 2020, the estimated antibody prevalence in the general population was between 3% and 10%.

“In light of those numbers, we believe that the prevalence of SARS-CoV-2 antibodies among the dental team is comparable to the general population in Germany. However, we have to underpin that these conclusions are based on weak evidence,” the researchers cautioned. “Our results, in line with other internationally published studies, confirm that current measures to reduce transmission continue to work against further transmission of SARS-CoV-2.”

The study, titled “Prevalence of SARS-CoV-2 IgG antibodies among dental teams in Germany”, was published online on 11 January 2022 in Clinical Oral Investigations, ahead of inclusion in an issue.