The association between influenza vaccination and the risk of SARS-CoV-2 infection, severeillness, and death: a systematic review of the literature.

We reviewed the association between seasonal influenza vaccination and the risk of SARS-CoV-2 infection or complicated illness or poor outcome (e.g. severe disease, need for hospitalization or ventilatory support, or death) among COVID-19 patients. None of the studies that were reviewed (n=12) found a significant increase in the risk of infection or in the illness severity or lethality, while some reported significantly inverse associations. Our findings support measures aimed at raising influenza vaccination coverage in the coming months.

Meta-analysis of diagnostic performance of serological tests for SARS-CoV-2 antibodies and public health implications

Serology-based tests have become a key public health element in the COVID-19 pandemic to assess the degree of herd immunity that has been achieved in the population. These tests differ between one another in several ways. Here, we conducted a systematic review and meta-analysis of the diagnostic accuracy of currently available SARS-CoV-2 serological tests, and assessed their real-world performance under scenarios of varying proportion of infected individuals. We included independent studies that specified the antigen used for antibody detection and used quantitative methods. We identified nine independent studies, of which six were based on commercial ELISA or CMIA/CLIA assays, and three on in-house tests. Test sensitivity ranged from 68% to 93% for IgM, from 65% to 100% for IgG, and from 83% to 98% for total antibodies. Random-effects models yielded a summary sensitivity of 82% (95%CI 75-88%) for IgM, and 85% for both IgG (95%CI 73-93%) and total antibodies (95%CI 74-94%). Specificity was very high for most tests, and its pooled estimate was 98% (95%CI 92-100%) for IgM and 99% (95%CI 98-100%) for both IgG and total antibodies. The heterogeneity of sensitivity and specificity across tests was generally high (I2>50%). In populations with a low prevalence ([≤]5%) of seroconverted individuals, the positive predictive value would be [≤]88% for most assays, except those reporting perfect specificity. Our data suggest that the use of serological tests for large-scale prevalence surveys (or to grant "immunity passports") are currently only justified in hard-hit regions, while they should be used with caution elsewhere.

Distribution of serotypes and patterns of antimicrobial resistance among commensal Streptococcus pneumoniae in nine European countries.

BACKGROUND: Streptococcus pneumoniae is a commensal of the human upper respiratory tract and a major cause of morbidity and mortality worldwide. This paper presents the distribution of serotypes and antimicrobial resistance in commensal S. pneumoniae strains cultured from healthy carriers older than four years of age in nine European countries. METHODS: Nasal swabs from healthy persons (age between 4 and 107 years old) were obtained by general practitioners from each country from November 2010 to August 2011. Swabs were cultured for S. pneumoniae using a standardized protocol. Antibiotic resistance was determined for isolated S. pneumoniae by broth microdilution. Capsular sequencing typing was used to identify serotypes, followed by serotype-specific PCR assays in case of ambiguous results. RESULTS: Thirty-two thousand one hundred sixty-one nasal swabs were collected from which 937 S. pneumoniae were isolated. A large variation in serotype distribution and antimicrobial resistant serotypes across the participating countries was observed. Pneumococcal vaccination was associated with a higher risk of pneumococcal colonization and antimicrobial resistance independently of country and vaccine used, either conjugate vaccine or PPV 23). CONCLUSIONS: Serotype 11A was the most common in carriage followed by serotypes 23A and 19A. The serotypes showing the highest resistance to penicillin were 14 followed by 19A. Serotype 15A showed the highest proportion of multidrug resistance.

Influenza vaccination coverage and reasons to refrain among high-risk persons in four European countries.

This paper examines influenza vaccine coverage using a population base of an average of 2300 persons in each of four European countries (Germany, Spain, Poland and Sweden). The reasons for non-vaccination of those in the high-risk groups were explored by questionnaire. The vaccine coverage rate (VCR) for elderly ranged from 18% in Poland to 67% in Spain. The VCR for high-risk population under 65 was 10% in Poland, 13% in Sweden, 27% in Germany and 30% in Spain. The most important reasons mentioned for not being vaccinated were: perceived sufficient resistance to flu (33-42%) in all countries; financial barriers in Poland (25%), and not to qualify for the vaccination (30%) and forgetfulness (20%) in Germany. Receiving a personal invitation for the vaccination, results in higher coverage rates in all four countries. We think that future interventions could be directed towards: an information campaign with special attention to the high-risk groups due to disease; promotion of personal invitations; and, for Poland, solving financial barriers to vaccination.