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Background: Seroepidemiological studies provide estimates of population-level immunity, prevalence/incidence of infections, and evaluation of vaccination programs. We assessed the seroprevalence of protective antibodies against influenza and evaluated the correlation of seroprevalence with the cumulative annual influenza incidence rate., Methods: We conducted an annual repeated cross-sectional seroepidemiological survey, during June-August, from 2014 to 2019, in Portugal. A total of 4326 sera from all age groups, sex, and regions was tested by hemagglutination inhibition assay. Seroprevalence and geometric mean titers (GMT) of protective antibodies against influenza were assessed by age group, sex, and vaccine status (65+ years old). The association between summer annual seroprevalence and the difference of influenza incidence rates between one season and the previous one was measured by Pearson correlation coefficient (r)., Results: Significant differences in seroprevalence of protective antibodies against influenza were observed in the population. Higher seroprevalence and GMT for A(H1N1)pdm09 and A(H3N2) were observed in children (5-14); influenza B seroprevalence in adults 65+ was 1.6-4.4 times than in children (0-4). Vaccinated participants (65+) showed significant higher seroprevalence/GMT for influenza. A strong negative and significant correlation was found between seroprevalence and ILI incidence rate for A(H1N1)pdm09 in children between 5 and 14 (r = -0.84; 95% CI, -0.98 to -0.07); a weak negative correlation was observed for A(H3N2) and B/Yamagata (r ≤ -0.1)., Conclusions: The study provides new insight into the anti-influenza antibodies seroprevalence measured in summer on the ILI incidence rate in the next season and the need for adjusted preventive health care measures to prevent influenza infection and transmission., (© 2024 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

Unlabelled: Toscana virus (TOSV) endemic in central Italy, has been documented in several European countries of the Mediterranean region. It is a neurotropic virus and in some of these countries studies to investigate seroprevalence have been done. In a recent etiologic study of meningitis we chose 106 of 308 samples to be tested for TOSV using a nested RT-PCR assay, and found six (5.6%) cases of meningitis by Toscana virus., Aim: To investigate the seroprevalence of antibodies against TOSV in a cohort of a population attended in our Hospital., Material and Methods: In serum samples collected for routine study we have investigated the presence of antibodies for TOSV. The study included samples of patients hospitalized and others observed in ambulatory and includes children and adults. Immunocompromised patients were excluded. The test was based on the-ELISA technique ((ENZYWELL), according to the manufacture instructions, being positive for a cut-off>1.2, negative if the cut-off <0.8 and doubtful if the cut-off >0.8 e <1.2., Results: 334 serum samples arbitrarily were used for seroprevalence study of antibodies to TOSV, 304 adults and 30 children. Positive results for anti-TOSV were obtained in 13 (3.9%) samples; in other 21 the result was doubtful and in those cases it was not possible to repeat because we have only one pair of serum and in the remaining 300 the result was negative. The positive samples were all from adults, 8 females and 5 males, 8 (62%) of them were older than 60 years. All children' samples were negative for TOSV antibodies., Conclusion: We documented a seroprevalence of 3.9% to TOSV, namely in adults older than 60 years. Our prevalence is lower when compared to other European countries, namely Spain (5-22%).

Objectives: Evidence for the utility of the new Mycobacterium tuberculosis (MTB) specific IFN-γ release assays in diagnosing latent tuberculosis infection (LTBI) is growing. However, data concerning conversion and reversion rates in serial testing of healthcare workers (HCWs) with an interferon-γ release assay are sparse., Methods: Between February 2007 and September 2009, 670 HCWs in the University Hospital of Porto, Portugal were tested at least twice with QuantiFERON-TB® Gold In-Tube (QFT) for LTBI. The tuberculin skin test (TST) was performed simultaneously. QFT was considered positive if INF-γ ≥0.35 IU/mL. TST conversion was defined as an increase ≥10 or ≥6 mm compared to a baseline TST <10 mm., Results: The second QFT was positive in 4.8% of the 376 HCWs with an INF-γ concentration at baseline below 0.1 IU/mL but in 48.8% of the 41 HCWs with an INF-γ concentration of 0.2 to <0.35 IU/mL. Out of 74 HCWs with a baseline INF-γ concentration ≥3.0 IU/mL, 4 (5.4%) reversed while 27 out of 55 HCWs (49%) with a baseline INF-γ concentration ≥0.35 to <0.7 IU/mL reversed to a negative QFT. Those 61 HCWs with TST conversion (increase ≥10 mm) were most often (78.7%) negative in both consecutive QFTs., Conclusion: Our data suggests the use of an uncertainty zone between 0.2 and 0.7 IU/mL in serial testing with QFT. As long as the knowledge regarding disease progression in QFT-positive persons is limited, persons pertaining to this zone should be retested before being offered preventive chemotherapy.

The prevalence of latent tuberculosis (TB) infection (LTBI) and the incidence of active tuberculosis in healthcare workers (HCWs) in a Portuguese hospital were examined. This cross-sectional study comprises 4,735 hospital workers screened between May 2005 and September 2008. Tuberculin skin test (TST) and interferon-gamma release assay (IGRA) were used simultaneously in 1,219 HCWs (25.7%). Radiographs were taken in symptomatic HCWs or in test-positive HCWs. The tests were repeated annually or bi-annually depending on risk assessment. IGRA was positive in 32.6% and TST in 74.2% of the HCWs. Years spent in healthcare were a risk factor for a positive IGRA, but not for a positive TST. Repeated bacillus Calmette-Guérin vaccination increased the probability of TST+/IGRA- discordance (35.4% versus 54.4%, respectively). In those tested three times with TST during the study period (n = 59), the mean diameter of TST increased from 5 to 7 to 10 mm. Within 3 yrs, 31 HCWs were diagnosed with active TB (annual incidence rate 191 out of 100,000 people). In eight HCWs with active TB, TST and IGRA were performed at the time of diagnosis and each test was positive. TB burden in HCWs in Portugal is high. With IGRA, the number of radiographs needed to exclude active TB could have been reduced by about half without missing a case of active TB. Therefore IGRA should be introduced into TB screening programmes.

Background: Upper respiratory tract infections are known to be a significant precipitant of acute asthma exacerbations. The aim of this study was to evaluate seasonal trends and the role of these pathogens in asthma exacerbations in school-aged children from Oporto (Portugal)., Methods: Nasal aspirates were collected from children aged 6 to 12 years old with asthma exacerbations attended in the Pediatric Emergency Department one day per week from January 1 to December 31, 2003. Demographic data, severity of asthma and asthma exacerbations, and current treatment were recorded. Samples were obtained through nasal wash with 1 ml saline and were processed by immunofluorescence assays (respiratory syncytial virus, adenovirus, parainfluenza and influenza virus), retrotranscription polymerase chain reaction (rhinovirus) and polymerase chain reaction (enterovirus, Chlamydia pneumoniae and Mycoplasma pneumoniae)., Results: In 54 eligible children, 37 nasal samples were obtained. Infectious agents were detected in 78 % of the patients. Rhinovirus was detected in 70.3 %, Mycoplasma pneumoniae in 16.2 %, enterovirus in 10.8 %, and Chlamydia pneumoniae in 2.7 %. Coinfection was identified in 21.6 % of the samples. There was no significant correlation between current treatment status, severity of asthma or exacerbations and the isolated agents. Two distinct peaks of asthma exacerbation were found, 40.5 % in spring and 32.4 % in autumn [corrected] The highest number of cases was recorded in March and the lowest in August and January. Rhinoviruses was detected in 27 % of the cases in autumn and in 24.3 % in spring [corrected], Conclusions: These results confirm the previously reported high frequency of rhinovirus detection in asthma exacerbations in children and provide evidence that asthma exacerbations and rhinovirus infections follow a seasonal pattern, occurring mostly in spring and autumn. The findings also underscore the frequency of Mycoplasma pneumoniae detection, and emphasize the importance of this agent as a possible trigger of asthma exacerbations.