Demographic and Travel Characteristics of Travel-Associated Zika Virus Infection Case-Patients in San Diego County,California (January 1, 2016–March 31, 2017)

Most Zika disease cases diagnosed in the continental US have been associated with travel to areas with risk of Zika transmission, mainly the Caribbean and Latin America. Limited information has been published about the demographic and travel characteristics of Zika case-patients in the United States, besides their age and gender. During 2016–2017 the County of San Diego Health and Human Services Agency, California, expanded the scope and completeness of demographic and travel information collected from Zika case-patients for public health surveillance purposes. The majority (53.8%) of travel-related Zika virus infection case-patients (n?=?78) in the county were Hispanic, significantly higher (p?≤?0.05) than the 33.0% of Hispanics in the county. Foreign-born residents, mainly from Mexico, were also overrepresented among cases compared to their share in the county population (33.3 vs. 23.0%; p?≤?0.05). Seventeen (21.8%) patients reported a primary language other than English (14 Spanish). Most case-patients traveled for tourism (54%) or to visit friends and relatives (36%). This surveillance information helps identify higher-risk populations and implement culturally targeted interventions for Zika prevention and control.     

Measles antibody levels among vaccinated and unvaccinated children 6–59 months of age in the Democratic Republic of the Congo, 2013–2014

BackgroundMeasles is endemic in the Democratic Republic of the Congo (DRC), and 89–94% herd immunity is required to halt its transmission. Much of the World Health Organization African Region, including the DRC, has vaccination coverage below the 95% level required to eliminate measles, heightening concern of inadequate measles immunity.MethodsWe assessed 6706 children aged 6–59 months whose mothers were selected for interview in the 2013–2014 DRC Demographic and Health Survey. History of measles was obtained by maternal report, and classification of children who had measles was completed using maternal recall and measles immunoglobulin G serostatus obtained from a multiplex chemiluminescent automated immunoassay dried blood spot analysis. A logistic regression model was used to identify associations of covariates with measles and seroprotection, and vaccine effectiveness (VE) was calculated.ResultsOut of our sample, 64% of children were seroprotected. Measles vaccination was associated with protection against measles (OR: 0.15, 95% CI: 0.03, 0.81) when administered to children 12 months of age or older. Vaccination was predictive of seroprotection at all ages. VE was highest (88%) among children 12–24 months of age.ConclusionOur results demonstrated lower than expected seroprotection against measles among vaccinated children. Understanding the factors that affect host immunity to measles will aid in developing more efficient and effective immunization programs in DRC.     

Estimated vaccine effectiveness against SARS-CoV-2 Delta and Omicron infections among health care workers and the general adult population in Norway,August 2021 – January 2022

BackgroundHealth care workers (HCW) have a higher exposure to SARS-CoV-2 virus than other professionals and to protect both HCW and patients, HCW have been prioritized for vaccination against SARS-CoV-2 in many countries. Estimating the COVID-19 vaccine effectiveness among HCW is important to provide recommendations to protect risk groups.MethodsWe estimated vaccine effectiveness against SARS-CoV-2 infections using Cox proportional hazard models among HCW with comparisons in the general population, from 1 August 2021 to 28 January 2022. Vaccine status is specified as a time-varying covariate and all models incorporated explicit time and were adjusted for age, sex, comorbidities, county of residence, country of birth, and living conditions. Data from the adult Norwegian population (aged 18–67 years) and HCW workplace data (as registered 1 January 2021) were collated from the National Preparedness Register for COVID-19 (Beredt C19).ResultsVaccine effectiveness was higher for Delta than for the Omicron variant in HCW (71 % compared to 19 %) as well as in non-HCW (69 % compared to −32 %). For the Omicron variant a 3rd dose provides significantly better protection against infection than 2 doses in both HCW (33 %) and non-HCW (10 %). Further, HCW seem to have better vaccine effectiveness than non-HCW for the Omicron, but not for the Delta variant.ConclusionsVaccine effectiveness were comparable between HCW and non-HCW for the delta variant, but significantly higher in HCW than non-HCW for the omicron variant. Both HCW and non-HCW got increased protection from a third dose.     

Varicella vaccination as useful strategy for reducing the risk of varicella-related hospitalizations in both vaccinated and unvaccinated cohorts (Italy, 2003–2018)

IntroductionThe present study summarizes evidences of the impact that varicella vaccination (VV) introduction and coverage can have on varicella attributable hospitalization rates.MethodsA retrospective observational study was carried out by considering hospital discharge records and VV coverage at 24 months collected from 2003 to 2018 by the Italian Ministry of Health. All hospitalizations records reporting an ICD-9 CM 052.X code as the principal diagnosis or any of the five secondary diagnoses were considered as related to varicella. The hospitalization rate reduction was evaluated by calculating average annual percent change (AAPC) through joint-point analysis.ResultsHospitalization rates showed a decreasing trend by age: children <1 year of age were the most affected group in each Italian administrative region (42.5/100,000 per year), whereas lower incidence rates were found in older age groups (23.8/100,000 in 1–5 years old and <4.0/100,000 in the following groups). Varicella hospitalization rates decreased significantly after the introduction of VV (3.4 vs. 2.7 per 100,000; p < 0.001). During the first five years after the introduction of vaccination, hospitalization rates showed a statistically significant decrease especially among infants <1 year of age (AAPC −35.0%; p < 0.001) and 1–5 years old (AAPC −35.2%; p < 0.01). Total percentage changes were −80.0% and −86.7%, in the age class <1 year old and 1–5 years old, respectively.ConclusionsAll the previously reported findings confirm that hospitalization rates are strictly related to both the vaccination coverage and the number of years since the introduction of the vaccination. VV confirms to be an important step in public health strategies and the introduction of universal vaccination, with high vaccination coverage, should be considered as an extremely powerful tool to reduce the risk of complications.     

Effectiveness of the COVID-19 vaccines on preventing symptomatic SARS-CoV-2 infections and hospitalizations in Southwestern Alaska,January–December 2021

The population in rural southwest Alaska has been disproportionately affected by COVID-19. To assess the benefit of COVID-19 vaccines, we analyzed data from the regional health system. We estimated vaccine effectiveness (VE) during January 16–December 3, 2021, against symptomatic SARS-CoV-2 infection after a primary series or booster dose, and overall VE against hospitalization. VE of a primary series against symptomatic infection among adult residents was 91.3% (95% CI: 85.7, 95.2) during January 16–May 7, 2021, 50.3% (95% CI, 41.1%–58.8%) during July 17–September 24, and 37.0% (95% CI, 27.8–45.0) during September 25–December 3, 2021; VE of a booster dose during September 25–December 3, 2021, was 92.1% (95% CI: 87.2–95.2). During the overall study period, VE against hospitalization was 91.9% (95% CI: 85.4–95.5). COVID-19 vaccination offered strong protection against hospitalization and a booster dose restored protection against symptomatic infection.