What's Next for Flu? Out-of-Season Circulation of Influenza Viruses in Southern Italy, August 2022

Occurrence of Circulating Antibodies against the Hemagglutinins of Influenza Viruses in the 2022/2023 Epidemic Season in Poland

The aim of this study was to determine the level of anti-hemagglutinin antibodies in blood sera collected from patients during the 2022/2023 epidemic season in Poland. A total of 700 sera samples from patients across the country were tested. The samples were divided into seven groups according to the age of the patients, with 100 samples from each age group. The hemagglutination inhibition test (OZHA) was used to determine the level of anti-hemagglutinin antibodies. The test results have confirmed the presence of anti-hemagglutinin antibodies for antigens A/Victoria/2570/2019 (H1N1)pdm09, A/Darwin/9/2021 (H3N2), B/Austria/1359417/2021 (B/Yamagata lineage) and B/ Phuket/3073/2013 (B/Victoria lineage) present in the influenza vaccine recommended by the World Health Organization (WHO) for the 2022/2023 epidemic season. The highest geometric mean antibody titres (GMT) and protection rate values (%) were recorded for hemagglutinin A/H3N2. In Poland, in the 2022/2023 epidemic season, the percentage of the population vaccinated against influenza was 5.7%. Therefore, the test results can be interpreted as the response of the immune system in patients who have been previously infected with an influenza virus.

Descriptive analysis to assess seasonal patterns of COVID-19 and influenza in low-income and middle-income countries in Asia, the Middle East and Latin America

OBJECTIVES

Understanding disease seasonality can help predict the occurrence of outbreaks and inform public health planning. Respiratory diseases typically follow seasonal patterns; however, knowledge regarding the seasonality of COVID-19 and its impact on the seasonality of influenza remains limited. The objective of this study was to provide more evidence to understand the circulation of SARS-CoV-2, the virus responsible for COVID-19, in an endemic scenario to guide potential preventive strategies.

DESIGN

In this study, a descriptive analysis was undertaken to describe seasonality trends and/or overlap between COVID-19 and influenza in 12 low-income and middle-income countries using Our World in Data and FluMart data sources. Plots of COVID-19 and influenza cases were analysed.

SETTING

Singapore, Thailand, Malaysia, the Philippines, Argentina, Brazil, Mexico, South Africa, Morocco, Bahrain, Qatar and Saudi Arabia.

OUTCOME MEASURES

COVID-19 cases and influenza cases.

RESULTS

No seasonal patterns of SARS-CoV-2 or SARS-CoV-2/influenza cocirculation were observed in most countries, even when considering the avian influenza pandemic period.

CONCLUSIONS

These results can inform public health strategies. The lack of observed seasonal behaviour highlights the importance of maintaining year-round vaccination rather than implementing seasonal campaigns. Further research investigating the influence of climate conditions, social behaviour and year-round preventive measures could be fundamental for shaping appropriate policies related to COVID-19 and respiratory viral disease control in low-income and middle-income countries as COVID-19 variant data and epidemiologic patterns accrue over time.

Epidemiology of bacterial co-infections and risk factors in COVID-19-hospitalized patients in Spain: a nationwide study

BACKGROUND

We performed a nationwide population-based retrospective study to describe the epidemiology of bacterial co-infections in coronavirus disease 2019 (COVID-19)-hospitalized patients in Spain in 2020. We also analyzed the risk factors for co-infection, the etiology and the impact in the outcome.

METHODS

Data were obtained from records in the Minimum Basic Data Set (MBDS) of the National Surveillance System for Hospital Data in Spain, provided by the Ministry of Health and annually published with 2 years lag. COVID-19 circulated in two waves in 2020: from its introduction to 31st June and from 1st July to 31st December. The risk of developing a healthcare-associated bacterial co-infection and the risk for in-hospital and intensive care unit (ICU) mortality in co-infected patients was assessed using an adjusted logistic regression model.

RESULTS

The incidence of bacterial co-infection in COVID-19 hospitalized patients was 2.3%. The main risk factors associated with bacterial co-infection were organ failure, obesity and male sex. Co-infection was associated with worse outcomes including higher in-hospital, in-ICU mortality and higher length of stay. Gram-negative bacteria caused most infections. Causative agents were similar between waves, although higher co-infections with Pseudomonas spp. were detected in the first wave and with Haemophilus influenzae and Streptococcus pneumoniae in the second.

CONCLUSIONS

Co-infections are not as common as those found in other viral respiratory infections; therefore, antibiotics should be used carefully. Screening for actual co-infection to prescribe antibiotic therapy when required should be performed.