Alexandria, Va., USA -- Dental care professionals are thought to be at enhanced risk of occupational exposure to SARS-CoV-2, but robust data to support this is lacking. The study "COVID-19: Seroprevalence and Vaccine Responses in UK Dental Care Professionals," published in the Journal of Dental Research (JDR), provides a longitudinal analysis of antibodies to SARS-CoV-2 spike glycoprotein, including early analysis of the impact of vaccination on the immune response.
In June 2020, I,507 West Midlands dental care professionals were recruited to test for baseline seroprevalence, or the proportion of the population that have circulating antibodies to SARS-CoV-2, indicating prior COVID-19 infection. The cohort was followed longitudinally for six months until January/February 2021 through the second wave of the COVID-19 pandemic in the United Kingdom and vaccination commencement.
Before enhanced personal protective equipment, natural infection with SARS-CoV-2 was significantly higher in dental care professionals. The baseline seroprevalence for dental care professionals was 16.3%, compared to estimates in the regional population of 6-7%. Following the introduction of increased infection control procedures, the rate of new infections in dental care practitioners was similar to the background population.
Seropositivity was retained in over 70% of participants at 3- and 6-month follow-up and conferred a 75% reduced risk of infection. Critically, only 5.3% of individuals infected in the first wave of COVID-19 produced a strong antibody response that provided robust protection from reinfection over 6 months. Even if antibodies waned, previous infection with SARS-CoV-2 led to a faster and stronger immune response following a single dose of the Pfizer-BioNTech 162b vaccine, indicating immunological memory.
"The data show that enhanced personal protective equipment used by dental care professionals is making a significant difference. The data also suggest that natural infection alone is unlikely to generate meaningful, durable herd immunity. This emphasizes the importance of vaccinations for controlling COVID-19" said JDR Editor-in-Chief Nicholas Jakubovics, Newcastle University, England. "This is an important and timely study with broad relevance that extends beyond the dental community."