The impact of SARS-CoV-2 on respiratory syndromic and sentinel surveillance in Israel, 2020: a new perspective on established systems.

BackgroundThe COVID-19 pandemic presented new challenges for the existing respiratory surveillance systems, and adaptations were implemented. Systematic assessment of the syndromic and sentinel surveillance platforms during the pandemic is essential for understanding the value of each platform in the context of an emerging pathogen with rapid global spread.AimWe aimed to evaluate systematically the performance of various respiratory syndromic surveillance platforms and the sentinel surveillance system in Israel from 1 January to 31 December 2020.MethodsWe compared the 2020 syndromic surveillance trends to those of the previous 3 years, using Poisson regression adjusted for overdispersion. To assess the performance of the sentinel clinic system as compared with the national SARS-CoV-2 repository, a cubic spline with 7 knots and 95% confidence intervals were applied to the sentinel network's weekly percentage of positive SARS-CoV-2 cases.ResultsSyndromic surveillance trends changed substantially during 2020, with a statistically significant reduction in the rates of visits to physicians and emergency departments to below previous years' levels. Morbidity patterns of the syndromic surveillance platforms were inconsistent with the progress of the pandemic, while the sentinel surveillance platform was found to reflect the national circulation of SARS-CoV-2 in the population.ConclusionOur findings reveal the robustness of the sentinel clinics platform for the surveillance of the main respiratory viruses during the pandemic and possibly beyond. The robustness of the sentinel clinics platform during 2020 supports its use in locations with insufficient resources for widespread testing of respiratory viruses.

Monitoring SARS-CoV-2 Activity with Sentinel Surveillance: Lessons Learned from the First Wave in Israel.

BACKGROUND: Guidelines for pandemic preparedness emphasize the role of sentinel and syndromic surveillance in monitoring pandemic spread. OBJECTIVES: To examine advantages and obstacles of utilizing a sentinel influenza surveillance system to monitor community severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) activity based on Israel's experience from mid-March to mid-May 2020. METHODS: Several modifications were applied to the influenza surveillance system. The clinical component relied mainly on pneumonia and upper respiratory infection (URI) consultations with primary care physicians as well as visits to emergency departments (ED) due to pneumonia. The virological data were based on nasopharyngeal swabs obtained from symptomatic patients who visited outpatient clinics. RESULTS: By week 12 of the pandemic, the crude and age-specific primary physician consultation rates due to URI and pneumonia declined below the expected level, reaching nadir that lasted from week 15 until week 20. Similarly, ED visits due to pneumonia were significantly lower than expected from weeks 14 and 15 to week 20. The virological surveillance started on week 13 with 6/253 of the swabs (2.3%) positive for SARS-CoV-2. There was a peak of 13/225 positive swabs on week 145.8%. During weeks 17-20, none of the swabs (47-97 per week) were positive for SARS-CoV-2. This trend was similar to national data. CONCLUSIONS: The virological component of the surveillance system showed the SARS-CoV-2 community spread, but had low sensitivity when virus activity was low. The clinical component, however, had no yield. Sentinel surveillance can assist in monitoring future novel pandemics and should be augmented in revised preparedness plans.

Effectiveness of BNT162b2 Vaccine Booster against SARS-CoV-2 Infection and Breakthrough Complications, Israel.

We estimated vaccine effectiveness (VE) of the BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) booster dose against SARS-CoV-2 infection and reduction of complications (hospitalization, severe disease, and death) among breakthrough cases in persons in Israel >16 years of age for <20 weeks. VE estimates reached 96.8% (95% CI 96.0%-97.5%) for persons 16-59 years of age and 93.1% (95% CI 91.8%-94.2%) for persons >60 years of age on week 3. VE estimates remained at these levels for 8 weeks in the 16-59 age group and 11 weeks in those >60. A slow decline followed, becoming more pronounced in the last 2-3 weeks of evaluation. Estimates in the last week of evaluation were 77.6% (95% CI 68.4%-84.2%) and 61.3% (52.5%-68.4%) for persons 16-59 years and >60 years, respectively. The more pronounced VE decline coincided with rapid increase in Omicron variant activity. Rate reduction of breakthrough complications remained moderate to high throughout the evaluation.

Lineage-matched versus mismatched influenza B vaccine effectiveness following seasons of marginal influenza B circulation.

BACKGROUND: Several countries have recently transitioned from the trivalent inactivated influenza vaccine (TIV) to the quadrivalent inactivated influenza vaccine (QIV) in order to outweigh influenza B vaccine-mismatch. However, few studies thus far evaluated its benefits versus the TIV in a systematic manner. Our objective was to compare the QIV VE with lineage-mismatched TIV VE. METHODS: We estimated the 2015-2016, 2017-2018, 2019-2020 end-of season influenza B VE against laboratory-confirmed influenza-like illness (ILI) among community patients, using the test-negative design. VE was estimated for pre-determined age groups and for moving age intervals of 15 years. RESULTS: Since 2011-2012 season, alternate seasons in Israel were dominated by influenza B circulation. Compared with the lineage-mismatched TIV used during the 2015-2016 and 2017-2018 seasons, the 2019-2020 QIV showed the highest all-ages VE, with VE estimates of 56.9 (95% CI 30.1 to 73.4), 16.5 (95% CI -22.5 to 43.1) and -25.8 (95% CI -85.3 to 14.6) for the 2019-2020, 2017-2018 and 2015-2016 seasons, respectively. The 2019-2020 VE point estimated were the highest for the 0.5-4, 5-17 and 18-44 years age groups and for more 15-year age intervals as compared to the other seasons. CONCLUSIONS: Our results support the rapid transition from the TIV to the QIV.