Interim 2018/19 influenza vaccine effectiveness: six European studies, October 2018 to January 2019

Intense interseasonal influenza outbreaks, Australia, 2018/19

BackgroundInterseasonal influenza outbreaks are not unusual in countries with temperate climates and well-defined influenza seasons. Usually, these are small and diminish before the main influenza season begins. However, the 2018/19 summer-autumn interseasonal influenza period in Australia saw unprecedented large and widespread influenza outbreaks.AimOur objective was to determine the extent of the intense 2018/19 interseasonal influenza outbreaks in Australia epidemiologically and examine the genetic, antigenic and structural properties of the viruses responsible for these outbreaks.MethodsThis observational study combined the epidemiological and virological surveillance data obtained from the Australian Government Department of Health, the New South Wales Ministry of Health, sentinel outpatient surveillance, public health laboratories and data generated by the World Health Organization Collaborating Centre for Reference and Research on Influenza in Melbourne and the Singapore Agency for Science, Technology and Research.ResultsThere was a record number of laboratory-confirmed influenza cases during the interseasonal period November 2018 to May 2019 (n= 85,286; 5 times the previous 3-year average) and also more institutional outbreaks, hospitalisations and deaths, than what is normally seen.ConclusionsThe unusually large interseasonal influenza outbreaks in 2018/19 followed a mild 2018 influenza season and resulted in a very early start to the 2019 influenza season across Australia. The reasons for this unusual event have yet to be fully elucidated but are likely to be a complex mix of climatic, virological and host immunity-related factors. These outbreaks reinforce the need for year-round surveillance of influenza, even in temperate climates with strong seasonality patterns.

[Effectiveness of annual flu vaccination until week four of season 2018/2019]

OBJECTIVE

Annual flu vaccination is the most effective measure to prevent the disease and its complications. Vaccine effectiveness (EV) varies from season to season, requiring annual re-evaluation. The objective of this work was to estimate the preliminary effectiveness of the influenza vaccine until epidemiological week 4 of the 2018/2019 season, in patients admitted to a third level hospital.

METHODS

The Test Negative Design (TDN) was carried out at the Hospital General Universitario de Alicante. Patients admitted with laboratory-confirmed influenza (RT-PCR positive for any influenza virus, in clinical sample of nasopharyngeal aspirate) and those with clinical suspicion of influenza and negative RT-PCR, from week 40 to week 4 of the 2018/2019 influenza season, were considered as controls. The vaccination coverage was calculated in the cases and in the controls, and the EV with its 95% confidence interval using the formula: EV = (1-Odds Ratio) x 100.

RESULTS

We included 524 patients: 58 cases and 466 controls. The overall EV for prevention of influenza cases was 42.5 % (95% CI -17.1 to 71.8) and for those over 1 year of age 63.7 % (95% CI 25.4 to 82.3).

CONCLUSIONS

The 2018-2019 influenza vaccine is effective in preventing influenza cases in patients admitted up to week 4 of the 2018-19 season. Results are preliminary and may vary and should be re-evaluated at the end of the season.

[Design and validation of a questionnaire on the attitudes of health professionals towards the official recommendation of influenza vaccination]

OBJECTIVE

Actually, there are no studies related to the attitudes of health professionals towards the official recommendation of influenza vaccination, despite the fact that there are numerous investigations that have addressed their own attitude towards vaccination. The objective is to design the Questionnaire on the Attitudes of Healthcare Professionals towards the Official Flu Vaccination Recommendations (CAPSVA).

METHODS

Quasi-experimental study. The control group includedInstrumental study was conducted between February and March 2019 with 288 professionals of Medicine, Nursing and Pharmacy of the Principado of Asturias (Spain). The sampling was non-probabilistic of incidental type. After content validation, a tool was designed with 16 items in three dimensions. Reliability (alpha ordinal) and internal validity (exploratory factorial analysis using the parallel analysis method) analyses were performed, as well as frequency analysis and mean comparisons.

RESULTS

The exploratory factor analysis yielded a 3-factor solution that explained 79.38% of the total variance. The ordinal alpha ranged from 0,72 to 0,80. The test-retest recorded a value of r= 0,804 (p < 0,001). There were no statistically significant differences when comparing according to sex (p = 0,952), professional group (p = 0,563) or having received influenza vaccination in the last campaign (p = 0,861). There were these differences when comparing the number of years of professional practice (p = 0,003) and having received specific training in vaccines in the last year (p = 0,004). More than 90% of the participants valued positively the influenza vaccination strategy of the Autonomous Community of study (quadrivalent vaccine for < 65 years and adjuvant trivalent for ≥65 years).

CONCLUSIONS

A questionnaire with sufficient guarantees of reliability and internal validity is available to evaluate the attitudes of health professionals towards the official recommendation of influenza vaccination.

Novel influenza A(H1N2) seasonal reassortant identified in a patient sample, Sweden, January 2019

In January 2019, a human seasonal reassortant influenza A(H1N2) virus with a novel 7:1 genetic constellation was identified in a 68-year-old female patient with suspected pneumonia. The virus harboured A(H3N2) neuraminidase and remaining genes from A(H1N1)pdm09. The patient recovered after severe illness. No additional cases have been detected. This is the second identified A(H1N2) seasonal reassortant in a human in Europe within 1 year; a previous case was detected in the Netherlands in March 2018.