Vaccinated COVID-19 Index Cases Are Less Likely to Transmit SARS-CoV-2 to Their Household Contacts: A Cohort Study.

The aim of this study was to evaluate the impact of index case vaccination on SARS-CoV-2 transmission to household contacts. In our epidemiological cohort study (May 2022-November 2023), we surveyed registered index case vaccination status and test results for contacts (testing on day 0, and on day 7 for negative contacts) and calculated the secondary attack rate (SAR), i.e., newly infected contacts/susceptible included contacts. The association of the independent variable, index case COVID-19 vaccination (yes/no), with household contact infection was determined using the adjusted odds ratio (aOR) and its 95% confidence interval (CI). We recorded 181 index cases and 314 contacts, of whom 250 agreed to participate; 16 contacts were excluded upon testing positive on day 0. Of the 234 included contacts, 49.1% were women, and the mean (SD) age was 51.9 (19.8) years. The overall SAR of 37.2% (87/234) was lower in the contacts of both vaccinated index cases (34.9% vs. 63.2%; p = 0.014) and index cases with a previous SARS-CoV-2 infection history (27.0% vs. 46.3%; p = 0.002). Index case vaccination showed a protective effect against infection for their household contacts (aOR = 0.21; 95% CI: 0.07, 0.67). The household SAR was high when the Omicron variant circulated. Vaccinated index cases were less likely to transmit SARS-CoV-2 to their contacts.

Effectiveness of maternal pertussis vaccination in protecting newborn: A matched case-control study.

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) × 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.

[Ebola alert: results and challenges in public health. A view from Catalonia (Spain)]. / Resultados y retos en salud pública ante la alerta por Ébola: una perspectiva desde Cataluña.

The Ebola outbreak in Guinea Conakry was notified to the World Health Organization (WHO) in March 2014. It is the most complex Ebola outbreak to date, affecting Guinea Conakry as well as the surrounding countries and with a risk of the disease spreading outside Africa. For this reason, the World Health Organization declared this Ebola outbreak an international public health emergency in August 2014. The Public Health Agency of Catalonia, through the Spanish Alert and Emergencies Coordination Network, initiated public health actions in March 2014, developing a single protocol of action to be applied by all the health care providers in the whole Catalan territory, advice for travellers and voluntary workers arriving from affected countries and a weekly newsletter addressed to health professionals. At the same time, the Ebola Analysis and Monitoring Committee and the Ebola Scientific and Advisory Committee were established. More than 9600 professional health workers attended training sessions and informative sessions. From August 2014, the Catalan Epidemiological Surveillance Emergency Service (SUVEC) reported 117 suspected Ebola cases, of which only 3 met the epidemiological and clinical criteria leading to the activation of the action protocol. All 3 cases proved negative for Ebola. Also, 95 voluntary workers were monitored, 52% of whom were female and 74% had returned from Sierra Leone. Dealing with the suspected Ebola cases required a detailed advance preparation and planning, with a coordinated effort between the epidemiological and health-care network, and all the agents involved, as well as precise, realistic and appropriate risk communication. The prior screening of suspected Ebola cases by the SUVEC meant the immediate protocol was activated only in the cases that met the epidemiological and clinical criteria. This is a key point to be reinforced in any future international public health alerts.

Factors associated to duration of hepatitis a outbreaks: implications for control.

Even though hepatitis A mass vaccination effectiveness is high, outbreaks continue to occur. The aim of this study was to investigate the association between duration and characteristics of hepatitis A outbreaks. Hepatitis A (HA) outbreaks reported between 1991 and 2007 were studied. An outbreak was defined as ≥2 epidemiologically-linked cases with ≥1 case laboratory-confirmed by detection of HA immunoglobulin M (IgM) antibodies. Relationships between explanatory variables and outbreak duration were assessed by logistic regression. During the study period, 268 outbreaks (rate 2.45 per million persons-year) and 1396 cases (rate 1.28 per 10(5) persons-year) were reported. Factors associated with shorter duration were time to intervention (OR = 0.96; 95% CI: 0.94-0.98) and school setting (OR = 0.39; 95% CI: 0.16-0.92). In person-to-person transmission outbreaks only time to intervention was associated with shorter outbreak duration (OR = 0.96; 95% CI: 0.95-0.98). The only variables associated with shorter outbreak duration were early administration of IG or vaccine and a school setting. Timely reporting HA outbreaks was associated with outbreak duration. Making confirmed HA infections statutory reportable for clinical laboratories could diminish outbreak duration.