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.

[Local public health networks. Apropos of an experience]. / Redes locales de salud pública. A propósito de una experiencia.

Public health action on a territory is complex and requires the involvement of multiple actors, who do not always act coordinately. Networks of organizations structures including the whole of the local actors facilitate the generation of synergies and enable greater effectiveness and efficiency of the joint action from the different actors on a same landscape. We present 3 years experience of four Public Health Committees in a region of Catalonia (Spain), composed by the main actors in public health planning. Each of the committees is organized on a plenary and working groups on issues arising from the regional health diagnosis, and coincident with the Health Plan of the Region. Coordination in no case implies the loss or dilution of the firm of the actor generator of intervention initiative in public health, but their empowerment and collaboration by the other actors. In conclusion welcomes the creation of a culture of collaboration and synergies between the different organizations concerned. Lack of specificity is observed in establishing operational objectives, and the need for greater coordination and involvement of the components of the various working groups.