We carried out a retrospective study of acute gastroenteritis (AGE) outbreaks reported between 1 January 2015 and 31 December 2021 in Catalonia (Spain) to compare the incidence from 2015 to 2019 with that observed from 2020 to 2021. We observed a higher incidence rate of outbreaks during the prepandemic period (16.89 outbreaks/1,000,000 person-years) than during the pandemic period (6.96 outbreaks/1,000,000 person-years) (rate ratio (RR) 0.41; 95% confidence interval (CI) 0.34 to 0.51). According to the aetiology of the outbreak, those of viral aetiology decreased from 7.82 to 3.38 outbreaks/1,000,000 person-years (RR 2.31; 95% CI 1.72 to 3.12), and those of bacterial aetiology decreased from 5.01 to 2.78 outbreaks/1,000,000 person-years (RR 1.80; 95% CI 1.29 to 2.52). There was a great reduction in AGE outbreaks in Catalonia. This reduction may have been due to the effect of the nonpharmaceutical measures applied to reduce the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the collapse of the healthcare system and epidemiological surveillance services may also have had a strong influence.

Introduction: The objective was to estimate the effectiveness of maternal pertussis vaccination in protecting infants aged < 2 months. Methods: We performed a case-control study. Laboratory-confirmed cases aged < 8 weeks at disease onset were identified and 2-4 matched-controls born within +/- 15 days of the case were included. Information was obtained from healthcare providers and maternal interviews. Odds ratios (OR) were calculated using multivariable conditional logistic regression. Vaccine effectiveness (VE) was estimated as (1 - OR) x 100%. Results: 47 cases and 124 controls were studied. The mean age (in days) (39.8 +/- 12.7 vs. 40.8 +/- 13.2), weeks of gestation (38.8 vs. 39.1, p = 0.43) and mean birth weight (3.309 vs. 3.253 kg, p = 0.55) were comparable between cases and controls. Mothers of cases were less frequently vaccinated in the third trimester (59.6% vs. 83.9%, p < 0.001). The VE of maternal vaccination in pregnancy was 88.0% (95%CI 53.8%-96.5%), and was slightly higher in those vaccinated before the 32nd week of gestation (88.5% vs 87.8%). Conclusion: Pertussis vaccination in pregnancy is very effective in reducing pertussis in children aged < 2 months. Vaccination before and after the 32nd week of pregnancy are equally effective in reducing the risk of pertussis. (c) 2021 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Norovirus infections are a leading cause of acute gastroenteritis outbreaks worldwide and across all age groups, with two main genogroups (GI and GII) infecting humans. The aim of our study was to investigate the occurrence of norovirus in saliva samples from individuals involved in outbreaks of acute gastroenteritis in closed and semiclosed institutions, and its relationship with the virus strain, virus shedding in stool, the occurrence of symptoms, age, and the secretor status of the individual. Epidemiological and clinical information was gathered from norovirus outbreaks occurring in Catalonia, Spain during 2017–2018, and stool and saliva samples were collected from affected and exposed resident individuals and workers. A total of 347 saliva specimens from 25 outbreaks were analyzed. Further, 84% of individuals also provided a paired stool sample. For GII infections, norovirus was detected in 17.9% of saliva samples from symptomatic cases and 5.2% of asymptomatic individuals. Positivity in saliva occurred in both secretors and nonsecretors. None of the individuals infected by norovirus GI was positive for the virus in saliva. Saliva positivity did not correlate with any of the studied symptoms but did correlate with age ≥ 65 years old. Individuals who were positive in saliva showed higher levels of virus shedding in stool. Mean viral load in positive saliva was 3.16 ± 1.08 log10 genome copies/mL, and the predominance of encapsidated genomes was confirmed by propidium monoazide (PMA)xx-viability RTqPCR assay. The detection of norovirus in saliva raises the possibility of oral-to-oral norovirus transmission during the symptomatic phase and, although to a lesser extent, even in cases of asymptomatic infections.

We retrospectively assessed the effectiveness of azithromycin in preventing transmission of pertussis to a patient’s household contacts. We also considered the duration between symptom onset in the primary patient and azithromycin administration. We categorized contacts into 4 groups: those treated within <7 days, 8–14 days, 15–21 days, and >21 days after illness onset in the primary patient. We studied 476 primary index patients and their 1,975 household contacts, of whom 4.5% were later identified as having pertussis. When contacts started chemoprophylaxis within <21 days after the primary patient’s symptom onset, the treatment was 43.9% effective. Chemoprophylaxis started >14 days after primary patient’s symptom onset was less effective. We recommend that contacts of persons with pertussis begin chemoprophylaxis within <14 days after primary patient’s symptom onset.

Acute gastroenteritis (AGE) is a leading cause of disease worldwide. The aim of this prospective observational study is to describe the epidemiology of AGE in closed and semi-closed institutions in Catalonia. In 2017, 151 outbreaks were reported; 30.5% occurred in closed and semi-closed institutions; 71.7% caused by norovirus (NoV) (1532) cases. Person-to-person transmission accounted for 75.8% of NoV outbreaks vs 46.1% in non-NoV outbreaks (p < 0.001). Attack rate for NoV outbreaks was 33.1% vs 14.3% for non-NoV outbreaks (RR = 2.3; 95%CI: 2.0–2.7). The high number of affected underscores prompt and intense preventive measures to avoid the extension and perpetuation of outbreaks in these settings.

On 16 March 2018, a nursing home notified a possible acute gastroenteritis outbreak that affected 11 people. Descriptive and case-control studies and analysis of clinical and environmental samples were carried out to determine the characteristics of the outbreak, its aetiology, the transmission mechanism and the causal food. The extent of the outbreak in and outside the nursing home was determined and the staff factors influencing propagation were studied by multivariate analysis. A turkey dinner on March 14 was associated with the outbreak (OR 4.22, 95% CI 1.11-16.01). Norovirus genogroups I and II were identified in stool samples. The attack rates in residents, staff and household contacts of staff were 23.49%, 46.22% and 22.87%, respectively. Care assistants and cleaning staff were the staff most frequently affected. Cohabitation with an affected care assistant was the most important factor in the occurrence of cases in the home (adjusted OR 6.37, 95% CI 1.13-36.02). Our results show that staff in close contact with residents and their household contacts had a higher risk of infection during the norovirus outbreak.

Seasonal influenza is a cause of hospitalization, especially in people with underlying disease or extreme age, and its severity may differ depending on the types and subtypes of circulating viruses. We investigated the factors associated with ICU admission or death in hospitalized patients with severe laboratory-confirmed influenza according to the viral type and subtype. An observational epidemiological study was carried out in patients aged ≥18 years from 12 Catalan hospitals between 2010 and 2016. For each reported case we collected demographic, virological and clinical characteristics. A mixed-effects logistic regression model was used to estimate crude and adjusted ORs. 1726 hospitalized patients were included: 595 (34.5%) were admitted to the ICU and 224 (13.0%) died. Lower ICU admission was associated with age ≥75 years in all influenza types and subtypes and with age 65-74 years for type A. In contrast, the 65-74 and ≥75 years age groups were associated with an increased risk of death in all types and subtypes, especially for type B (aOR 27.42, 95% CI: 4.95-151.93 and 15.96; 95% CI: 3.01-84.68). The comorbidity most closely associated with severe outcomes was immune deficiency, which was associated with death for type B (aOR 9.02, 95% CI: 3.05-26.69) and subtype A(H1N1)pdm09 (aOR 3.16, 95% CI: 1.77-5.66). Older age was a differential factor for ICU admission and death: it was associated with lower ICU admission but a risk factor for death. The comorbidity with the closest association with death was immune deficiency, mainly in influenza type B patients.

La enfermedad neumocócica es una importante causa de morbimortalidad. La descripción de casos de identificación post mortem de Streptococcus pneumoniae (SP) es infrecuente. Presentamos un caso de fallecimiento por sepsis fulminante secundaria a SP en una mujer joven con factores de riesgo. Se trata de un fallecimiento comunicado por urgencias hospitalarias como una parada cardiaca extrahospitalaria de posible origen abdominal. La autopsia judicial reveló hallazgos compatibles con un cuadro de sepsis fulminante, por lo que se comunicó a vigilancia epidemiológica de salud pública. Se realizaron estudios microbiológicos post mortem, que permitieron aislar SP en el cultivo de líquido pleural, posteriormente la PCR en sangre identificó SP y se caracterizó el serotipo (22F). A pesar de que la hipoesplenia era conocida desde la adolescencia y ser una indicación de vacunación, la paciente no estaba vacunada frente al SP por ninguna de las 2 vacunas actualmente recomendadas en España.

SummaryAt the end of 1998, universal hepatitis A+B vaccination of 12 year olds was introduced in Catalonia. The aim was to examine trends in hepatitis A during 2005‐2015 and assess risk factors by age group. We carried out an observational epidemiological study of the incidence and risk factors of hepatitis A reported to the surveillance system. Information on exposure was recorded for each case for the 2‐6 weeks before symptom onset. Spearman's coefficient was used to evaluate the trends of rates. The chi‐square test was used to compare categorical. We studied 2621 hepatitis A cases; the age mean was 26.6 years (SD=18.2), and >50% of cases were in the 20‐49 years age group. The incidence decreased from 3.28/100 000 in 2005 to 1.50/100 000 in 2015. The rate for women decreased over time (P = .008), but the reduction was not significant in men (P = .234). Men consistently had higher rates than women with the biggest difference being in the 20‐34 years age group (rate 8.8 vs 2.8). The greatest risk factor was travel to an endemic country (42.1%) in the 0‐19 years age group and male‐to‐male sexual contact (18.6%) in the 20‐49 years age group. The case fatality rate in adults aged >49 years was 0.4%. In conclusion, the vaccination programme of preadolescents resulted in a reduction in hepatitis A cases. However, a significant amount of cases still appear in immigrants and men who have sex with men. Hepatitis A in adults is an emerging health problem that will require new strategies.

The Plan of Information on Acute Respiratory Infections in Catalonia (PIDIRAC) included the surveillance of severe hospitalized cases of laboratory-confirmed influenza (SHCLCI) in 2009. The objective of this study was to determine the clinical, epidemiological and virological features of SHCLCI recorded in 12 sentinel hospitals during five influenza seasons.

Hepatitis A (HA) has been a vaccine-preventable disease since 1995. In Catalonia, a universal combined hepatitis A+B vaccination program of preadolescents was initiated at the end of 1998. However, outbreaks are reported each year and post-exposure prophylaxis (PEP) with hepatitis A virus (HAV) vaccine or immunoglobulin (IG) is recommended to avoid cases. The aim of this study was to assess the effectiveness of HAV vaccine and IG in preventing hepatitis A cases in susceptible exposed people. A retrospective cohort study of contacts of HA cases involved in outbreaks reported in Catalonia between January 2006 and December 2012 was made. The rate ratios and 95% confidence intervals (CI) of HA in susceptible contacts receiving HAV or IG versus those without PEP were calculated. There were 3550 exposed persons in the outbreaks studied: 2381 received one dose of HAV vaccine (Hepatitis A or hepatitis A+B), 190 received IG, and 611 received no PEP. 368 exposed subjects received one dose of HAV vaccine and IG simultaneously and were excluded from the study. The effectiveness of PEP was 97.6% (95% CI 96.2-98.6) for HAV vaccine and 98.3% (95% CI 91.3-99.9) for IG; the differences were not statistically significant (p = 0.36). The elevated effectiveness of HAV vaccination for PEP in HA outbreaks, similar to that of IG, and the long-term protection of active immunization, supports the preferential use of vaccination to avoid secondary cases.

Aim: To characterize the genetic diversity of unrelated Legionella pneumophila clinical isolates in Catalonia and compare with other European regions. Methods: 95 unrelated isolates were analyzed using monoclonal antibodies and sequence-based typing, 1989-2013. Results: The isolates showed a high diversity (IOD 0.964) with a predominance of some profiles (ST37-Phialdelphia, ST23-Philadelphia and ST1-OLDA). All regions had predominant sequence types (STs) that differed between regions, and only 3% of STs were shared between the three regions. Conclusion: L. pneumophila clinical isolates from Catalonia presented a high diversity and can be used in epidemiological surveillance studies. The heterogeneous predominance of STs between European regions suggested a relationship between geographical distribution and virulence of some STs.

Pertussis vaccination with 4–5 doses of acellular vaccines is recommended in Spain to all children at 2 months to 6 years of age. The effectiveness of the acellular pertussis vaccination was assessed in this study by comparing the incidence of secondary pertussis in vaccinated (4–5 doses) and unvaccinated or partially vaccinated (0–3 doses) household contacts 1–9 years old of confirmed cases of pertussis in Spain in 2012–13. Eighty-five percent of contacts had been vaccinated with 4–5 doses of acellular pertussis vaccines. During the 2-year study period, 64 cases of secondary pertussis were detected among 405 household contacts 1–9 years old: 47 among vaccinated and 17 among unvaccinated or partially vaccinated contacts. The effectiveness for preventing secondary pertussis, calculated as 1 minus the relative risk (RR) of secondary pertussis in vaccinated vs. unvaccinated/partially vaccinated contacts, was 50 % [95 % confidence interval (CI): 19–69 %, p < 0.01] when household contacts were vaccinated using DTaP, Tdap, hexavalent or heptavalent vaccines, and it was 51.3 % (95 % CI: 21–70 %, p < 0.01) when they were vaccinated using DTaP or TdaP vaccines. The effectiveness adjusted for age, sex, pertussis chemotherapy and type of household contact was 58.6 % (95 % CI: 17–79 %, p < 0.05) when contacts were vaccinated using available acellular vaccines, and it was 59.6 % (95 % CI: 18–80 %, p < 0.01) when they were vaccinated using DTaP vaccines. Acellular pertussis vaccination during childhood was effective for preventing secondary pertussis in household contacts 1–9 years old of pertussis cases in Catalonia and Navarra, Spain.

•Over 25% of outbreaks of hepatitis A are generated by immigrant index cases.•The main risk factor for immigrant index cases of hepatitis A is travel to their country of origin.•We recommend hepatitis A vaccination in immigrants travelling internationally.

A hepatitis A+B vaccine vaccination program of 12-year-olds was introduced in Catalonia in 1998. The aim of this study was to investigate the evolution of hepatitis A outbreaks in Catalonia and estimate the preventable fraction of cases associated with outbreaks as a measure of the impact of the vaccination program. Hepatitis A outbreaks reported to the Health Department between 1991 and 2012 were analyzed. The incidence rates of outbreaks, outbreak-associated cases and hospitalizations were calculated. The preventable fraction (PF) and 95% confidence intervals (CI) were estimated for the whole study period (pre-vaccination and post-vaccination) and the post-vaccination period. One-hundred-eight (108) outbreaks (rate of 2.21 per 106 persons-year) were reported in the pre-vaccination period and 258 outbreaks (rate of 2.82 per 106 persons-year) in the post-vaccination period. The rate of cases associated with outbreaks was 1.52 per 105 persons-year in the pre-vaccination period and 1.28 per 105 persons-year in the post-vaccination period. Hospitalization rates were 0.08 and 0.75 per 106 persons-year, respectively. The number of person-to-person outbreaks whose index case was a school contact decreased in the post-vaccination period (aOR 2.72; 95%CI 1.35–5.48), but outbreaks whose index case was a man who has sex with men (MSM) or an immigrant increased. The PF of all outbreak-associated cases was 6.46% (95%CI 3.11–9.82) and the highest PF was in the 15–24 years age group (42.53%; 95%CI 29.30–55.75). In the 0–4 years age group, the PF was 18.35% (95%CI 9.59–27.11), suggesting a protective herd effect in unvaccinated subjects. Vaccination of immigrants traveling to endemic countries and MSM should be reinforced.

The Caliciviridae family includes norovirus and sapovirus, which both cause acute gastroenteritis (AGE). Currently, norovirus is the most common cause of AGE in all age groups in many countries. We analysed clinical differences in reported cases of acute gastroenteritis caused by caliciviruses (AGC) by age group and agent involved. We conducted a descriptive study of AGE outbreaks reported to the Public Health Agency of Catalonia (Spain) in 2010 and 2011. The odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to estimate the association between clinical symptoms and age. Clinical differences between the <15 years and ≥15 years age groups were statistically significant: children more frequently presented with vomiting (OR, 3.25; 95% CI, 2.56-4.13), abdominal pain (OR, 3.27; 95% CI, 2.60-4.12), fever (OR, 1.51; 95% CI, 1.17-1.96) and nausea (OR, 1.49; 95% CI, 1.19-1.85). Comparing clinical manifestations of sapovirus and norovirus infection in children aged <15 years, cases caused by norovirus more frequently presented with vomiting and fever (p <0.001), and cases caused by sapovirus more frequently presented with diarrhoea (p 0.013). Determination of the clinical differences associated with cases in outbreaks according to the age of the majority of cases and the symptoms most frequently detected may aid decision making and guide aetiological investigations and the adoption of prevention and control measures.

OBJECTIVE: To determine the risk of latent tuberculous infection (LTBI) among contacts of smokers with tuberculosis (TB).METHODS: A study was conducted to determine the prevalence of LTBI among contacts of TB cases aged >14 years in Catalonia, Spain. A survey was carried out for each TB case and their contacts. LTBI was diagnosed using the tuberculin skin test (>= 5 mm). The risk of LTBI associated with smoking was determined by multivariate logistic regression analysis, with adjusted odds ratio (aOR) and their 95% confidence intervals (CI).RESULTS: The smoking prevalence among TB cases was 40.7% (439/1079). The prevalence of LTBI among their contacts was 29.7% (2281/7673). It was higher among contacts of smoking index cases (35.3%) than among those of non-smokers (25.7%). Smoking was independently associated with an increased risk of LTBI among contacts (aOR 1.5, 95 %CI 1.3-1.7), and was estimated to be responsible for 12.8% of infections.CONCLUSIONS: Index case smoking increases the risk of LTBI and should be systematically investigated. A reduction in smoking could lower the risk of infection substantially.

Measles cases in the European Region have been increasing in the last decade; this illustrates the challenge of what we are now encountering in the form of pediatric preventable diseases. In Catalonia, autochthonous measles was declared eliminated in the year 2000 as the result of high measles-mumps-rubella vaccine (MMR) coverage for first and second dose (15 mo and 4 y) since the mid-1990s. From then on, sporadic imported cases and small outbreaks appeared, until in 2006–2007 a large measles outbreak affecting mostly unvaccinated toddlers hit the Barcelona Health Region. Consequently, in January 2008, first dose administration of MMR was lowered from 15 to 12 mo of age. A new honeymoon period went by until the end of 2010, when several importations of cases triggered new sustained transmission of different wild measles virus genotypes, but this time striking young adults. The aim of this study is to show the effect of a change in MMR vaccination schedule policy, and the difference in age incidence and hospitalization rates of affected individuals between both outbreaks. Epidemiologic data were obtained by case interviews and review of medical records. Samples for virological confirmation and genotyping of cases were collected as established in the Measles Elimination plan guidelines. Incidence rate (IR), rate ratio (RR) and their 95% CI and hospitalization rate (HR) by age group were determined. Statistic z was used for comparing proportions. Total number of confirmed cases was 305 in the 2010 outbreak and 381 in the 2006–2007 outbreak; mean age 20 y (SD 14.8 y; 3 mo to 51 y) vs. 15 mo (SD 13.1 y; 1 mo to 50 y). Highest proportion of cases was set in ≥ 25 y (47%) vs. 24.2% in 2006 (p < 0.001). Differences in IR for ≤ 15 mo (49/100,000 vs. 278.2/100,000; RR: 3,9; 95%CI 2,9–5.4) and in overall HR 29.8% vs. 15.7% were all statistically significant (p < 0.001). The change of the month of age for the administration of the first MMR dose proved successful to protect infants. Yet, given the current epidemiological situation, continued awareness and efforts to reach young adult population, especially those at high risk of infection and transmission such as healthcare workers and travelers, are needed to stop the spread of the virus when importations occur.

Between January 2012 and June 2013, 27 sexually transmitted infections were reported in adolescents aged 13-15 years in Catalonia, Spain. In the first half of 2013, there were nine cases of gonorrhoea, while in the same period of 2012, there was one. In June 2013, two gonorrhoea cases aged 13-14 years, linked to a common source through a social network, were reported. The public health response should be adapted to this vulnerable population.