Eurosurveillance - Volume 28, Issue 4, 26 January 2023

Timely treatment with neuraminidase inhibitors (NAI) can reduce severe outcomes in influenza patients.

We assessed the impact of antiviral treatment on in-hospital deaths of laboratory-confirmed influenza patients in 11 European Union countries from 2010/11 to 2019/20.

Case-based surveillance data from hospitalised patients with known age, sex, outcome, ward, vaccination status, timing of antiviral treatment, and hospitalisation were obtained. A mixed effect logistic regression model using country as random intercept was applied to estimate the adjusted odds ratio (aOR) for in-hospital death in patients treated with NAIs vs not treated.

Of 19,937 patients, 31% received NAIs within 48 hours of hospital admission. Older age (60–79 years aOR 3.0, 95% CI: 2.4–3.8; 80 years 8.3 (6.6–10.5)) and intensive care unit admission (3.8, 95% CI: 3.4–4.2) increased risk of dying, while early hospital admission after symptom onset decreased risk (aOR 0.91, 95% CI: 0.90–0.93). NAI treatment initiation within 48 hours and up to 7 days reduced risk of dying (0–48 hours aOR 0.51, 95% CI: 0.45–0.59; 3–4 days 0.59 (0.51–0.67); 5–7 days 0.64 (0.56–0.74)), in particular in patients 40 years and older (e.g. treatment within 48 hours: 40–59 years aOR 0.43, 95% CI: 0.28–0.66; 60–79 years 0.50 (0.39–0.63); ≥80 years 0.51 (0.42–0.63)).

NAI treatment given within 48 hours and possibly up to 7 days after symptom onset reduced risk of in-hospital death. NAI treatment should be considered in older patients to prevent severe outcomes.

The PCR quantification cycle (Cq) is a proxy measure of the viral load of a SARS-CoV-2-infected individual.

To investigate if Cq values vary according to different population characteristics, in particular demographic ones, and within the COVID-19 pandemic context, notably the SARS-CoV-2 type/variant individuals get infected with.

We considered all positive PCR results from Cheshire and Merseyside, England, between 6 November 2020 and 8 September 2021. Cq distributions were inspected with Kernel density estimates. Multivariable quantile regression models assessed associations between people’s features and Cq.

We report Cq values for 188,821 SARS-CoV-2 positive individuals. Median Cqs increased with decreasing age for suspected wild-type virus and Alpha variant infections, but less so, if not, for Delta. For example, compared to 30–39-year-olds (median age group), 5–11-year-olds exhibited 1.8 (95% CI: 1.5 to 2.1), 2.2 (95% CI: 1.8 to 2.6) and 0.8 (95% CI: 0.6 to 0.9) higher median Cqs for suspected wild-type, Alpha and Delta positives, respectively, in multivariable analysis. 12–18-year-olds also had higher Cqs for wild-type and Alpha positives, however, not for Delta. Overall, in univariable analysis, suspected Delta positives reported 2.8 lower median Cqs than wild-type positives (95% CI: 2.7 to 2.8; p < 0.001). Suspected Alpha positives had 1.5 (95% CI: 1.4 to 1.5; p < 0.001) lower median Cqs than wild type.

Wild-type- or Alpha-infected school-aged children (5–11-year-olds) might transmit less than adults (> 18 years old), but have greater mixing exposures. Smaller differences in viral loads with age occurred in suspected Delta infections. Suspected-Alpha- or Delta-infections involved higher viral loads than wild type, suggesting increased transmission risk. COVID-19 control strategies should consider age and dominant variant.