Comparison of Nasopharyngeal and Saliva Swab Nucleic Acid Amplification and Rapid Antigen Testing To Detect Omicron SARS-CoV-2 Variant of Concern: a Prospective Clinical Trial (OMICRON).

In November 2021, the World Health Organization declared the Omicron variant (B.1.1.519) a variant of concern. Since then, worries have been expressed regarding the ability of usual diagnostic tests to detect the Omicron variant. In addition, some recently published data suggested that the salivary reverse transcription (RT)-PCR might perform better than the current gold standard, nasopharyngeal (NP) RT-PCR. In this study, we aimed to compare the sensitivities of nasopharyngeal and saliva RT-PCR and assess the diagnostic performances of rapid antigen testing (RAT) in nasopharyngeal and saliva samples. We conducted a prospective clinical study among symptomatic health care professionals consulting the occupational health service of our hospital for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) screening and hospitalized patients in internal medicine/intensive care wards screened for SARS-CoV-2 with COVID-19-compatible symptoms. A composite outcome considering NP PCR and/or saliva PCR was used as a reference standard to define COVID-19 cases. A total of 475 paired NP/saliva specimens have been collected with a positivity rate of 40% (n = 192). NP and salivary RT-PCR exhibited sensitivities of 98% (95% CI, 94 to 99%) and 87% (95% CI, 81 to 91%), respectively, for outpatients (n = 453) and 94% (95% CI, 72 to 99%) and 69% (95% CI, 44 to 86%), respectively, for hospitalized patients (n = 22). Nasopharyngeal rapid antigen testing exhibited much lower diagnostic performances (sensitivity of 66% and 31% for outpatients and inpatients, respectively), while saliva RAT showed a sensitivity of less than 5% in both groups. Nasopharyngeal RT-PCR testing remains the gold standard for SARS-CoV-2 Omicron variant screening. Salivary RT-PCR can be used as an alternative in case of contraindication to perform NP sampling. The use of RAT should be limited to settings where access to molecular diagnostic methods is lacking. IMPORTANCE The Omicron variant of concern spread rapidly since it was first reported in November 2021 and currently accounts for the vast majority of new infections worldwide. Recent reports suggest that saliva sampling might outweigh nasopharyngeal sampling for the diagnosis of the Omicron variant. Nevertheless, data investigating the best diagnostic strategy specifically for the Omicron variant of concern remain scarce. This study fills this gap in current knowledge and elucidates the question of which strategy to use in which patient. It provides a new basis for further improving COVID-19 screening programs and managing patients suspected to have COVID-19.

Promotion of the influenza vaccination to hospital staff during pre-employment health check: a prospective, randomised, controlled trial.

BACKGROUND: Vaccination is the most effective prevention of seasonal influenza. Despite its recommendation and active promotion, vaccination coverage remains low among healthcare staff. The goal of the study was to test if a pre-employment health check is a good opportunity to promote future vaccination against influenza among healthcare workers newly hired by a university hospital. METHODS: All new hospital employees active at the bedside who underwent a pre-employment health check between the end of 2016's influenza epidemic and the start of the next influenza vaccination campaign were randomly allocated to a control group or an intervention group. The intervention consisted of a semi-structured dialog and the release of an information leaflet about influenza and influenza vaccination during the check-up, and the shipment of a postcard reminder 2 weeks before the next vaccination campaign. Vaccination rates during the campaign were compared among the two groups. RESULTS: Three hundred fifty-seven employees were included. Vaccination rates were similar in both groups: 79/172 (46%) in the control and 92/185 (50%) in the intervention group. A significantly higher rate of vaccination was noted among physicians (70/117, 60%) than among other employees (101/240, 42%, p = 0.001). In a pre-defined exploratory analysis among physicians, the vaccination rate was higher in the intervention group (36/51, 71%) than in the control group (34/65, 52%, p = 0.046). CONCLUSIONS: Promotion of the influenza vaccine during pre-employment health check did not improve the vaccination rate of newly hired hospital healthcare workers overall during the next influenza vaccination campaign. Results suggest a favourable impact on the vaccination rate of physicians. Thus, there may be an interest in using communication strategies tailored to the different categories of healthcare workers to promote the influenza vaccine during pre-employment health check. TRIAL REGISTRATION: ClinicalTrials, NCT02758145 . Registered 26 April 2016.