Incidence of Influenza in Healthy Adults and Healthcare Workers: A Systematic Review and Meta-Analysis

BACKGROUND: Working in healthcare is often considered a risk factor for influenza; however, this risk has not been quantified. We aimed to systematically review evidence describing the annual incidence of influenza among healthy adults and healthcare workers (HCWs). METHODS AND FINDINGS: We searched OVID MEDLINE (1950 to 2010), EMBASE (1947 to 2010) and reference lists of identified articles. Observational studies or randomized trials reporting full season or annual influenza infection rates for healthy, working age adult subjects and HCWs were included. Influenza infection was defined as a four-fold rise in antibody titer, or positive viral culture or polymerase chain reaction. From 24,707 citations, 29 studies covering 97 influenza seasons with 58,245 study participants were included. Pooled influenza incidence rates (IR) (95% confidence intervals (CI)) per 100 HCWs per season and corresponding incidence rate ratios (IRR) (95% CI) as compared to healthy adults were as follows. All infections: IR 18.7 (95% CI, 15.8 to 22.1), IRR 3.4 (95% CI, 1.2 to 5.7) in unvaccinated HCWs; IR 6.5 (95% CI, 4.6 to 9.1), IRR 5.4 (95% CI, 2.8 to 8.0) in vaccinated HCWs. Symptomatic infections: IR 7.5 (95% CI, 4.9 to 11.7), IRR 1.5 (95% CI, 0.4 to 2.5) in unvaccinated HCWs, IR 4.8 (95% CI, 3.2 to 7.2), IRR 1.6 (95% CI, 0.5 to 2.7) in vaccinated HCWs. CONCLUSIONS: Compared to adults working in non-healthcare settings, HCWs are at significantly higher risk of influenza

The everchanging epidemiology of meningococcal disease worldwide and the potential for prevention through vaccination.

Neisseria meningitidis is a major cause of bacterial meningitis and septicaemia worldwide and is associated with high case fatality rates and serious life-long complications among survivors. Twelve serogroups are recognised, of which six (A, B, C, W, X and Y) are responsible for nearly all cases of invasive meningococcal disease (IMD). The incidence of IMD and responsible serogroups vary widely both geographically and over time. For the first time, effective vaccines against all these serogroups are available or nearing licensure. Over the past two decades, IMD incidence has been declining across most parts of the world through a combination of successful meningococcal immunisation programmes and secular trends. The introduction of meningococcal C conjugate vaccines in the early 2000s was associated with rapid declines in meningococcal C disease, whilst implementation of a meningococcal A conjugate vaccine across the African meningitis belt led to near-elimination of meningococcal A disease. Consequently, other serogroups have become more important causes of IMD. In particular, the emergence of a hypervirulent meningococcal group W clone has led many countries to shift from monovalent meningococcal C to quadrivalent ACWY conjugate vaccines in their national immunisation programmes. Additionally, the recent licensure of two protein-based, broad-spectrum meningococcal B vaccines finally provides protection against the most common group responsible for childhood IMD across Europe and Australia. This review describes global IMD epidemiology across each continent and trends over time, the serogroups responsible for IMD, the impact of meningococcal immunisation programmes and future needs to eliminate this devastating disease

Demonstration of background rates of three conditions of interest for vaccine safety surveillance.

IntroductionAdverse events following immunization (AEFIs) are unwanted or unexpected health outcomes following vaccination, which may or may not be causally-linked to vaccines. AEFI reporting is important to post-marketing vaccine safety surveillance and has the potential to identify new or rare AEFIs, show increases in known AEFIs, and help to maintain public confidence in vaccine programs. Knowledge of the expected incidence (i.e. background rate) of a possible AEFI is essential to the investigation of vaccine safety signals. We selected three rarely reported AEFIs representing the spectrum of causal association with vaccines, from proven (immune thrombocytopenia [ITP]) to questioned (Kawasaki disease [KD]) to unsubstantiated (multiple sclerosis [MS]) and determined their background rates.MethodsWe extracted data on hospitalizations (CIHI Discharge Abstract Database) for ITP, KD, and MS among Ontario children for the period 2005 to 2014 from IntelliHEALTH. As ITP can be managed without hospitalization, we also extracted emergency department (ED) visits from the CIHI National Ambulatory Care Reporting System. For all conditions, we only counted the first visit and if the same child had both an ED visit and a hospitalization for ITP, only the hospitalization was included. We calculated rates by year, age group and sex using population estimates from 2005-2014, focusing on age groups within the Ontario immunization schedule around vaccine(s) of interest.ResultsPer 100,000 population, annual age-specific incidence of ITP in children age 1 to 7 years ranged from 8.9 to 12.2 and annual incidence of KD in children less than 5 years ranged from 19.1 to 32.1. Average annualized incidence of adolescent (11-17 years) MS across the study period was 0.8 per 100,000.DiscussionDespite limitations, including lack of clinical validation, this study provides an example of how health administrative data can be used to determine background rates which may assist with interpretation of passive vaccine safety surveillance

HIV Prophylaxis in High Risk Newborns: An Examination of Sociodemographic Factors in an Inner City Context

Background. Perinatal HIV transmission is less than 1% with antiretroviral (ARV) prophylaxis. Transmission risk appears higher in "high risk" dyads, yet this is not well defined, possibly exposing more infants to combination ARV compared with standard care. Objective. To describe characteristics of mother-infant dyads where infants received ARVs and how these characteristics relate to specific ARV regimens. Methods. Retrospective chart review of ARV-receiving newborns at St. Michael's Hospital from 2007 to 2012 (and their mothers). Numerical and categorical variables were analyzed using -tests/ANOVA -tests and Fisher's exact tests, respectively. Results. Maternal HIV status at delivery was as follows: 69% positive and 24% unknown. Maternal factors significantly associated with newborn-triple therapy are Canadian origin, substance abuse, unstable housing, lost custody of previous children, and sex work. Neonatal factors are child protective services involvement, NICU, and lengthier admission. Maternal factors associated with monotherapy are African origin, HIV-positive, employment, and education. Further analysis based on maternal presentation at delivery demonstrated unequal distribution of many aforementioned factors. Discussion. This cohort revealed associations between particular factors and newborn-monotherapy or triple therapy that exist, suggesting that sociodemographic factors may influence the choice of ARV regimen. Canadian perinatal HIV transmission guidelines should qualify how to risk stratify newborns and consider use of rapid HIV antibody testing

HIV Prophylaxis in High Risk Newborns: An Examination of Sociodemographic Factors in an Inner City Context

Background. Perinatal HIV transmission is less than 1% with antiretroviral (ARV) prophylaxis. Transmission risk appears higher in “high risk” dyads, yet this is not well defined, possibly exposing more infants to combination ARV compared with standard care. Objective. To describe characteristics of mother-infant dyads where infants received ARVs and how these characteristics relate to specific ARV regimens. Methods. Retrospective chart review of ARV-receiving newborns at St. Michael’s Hospital from 2007 to 2012 (and their mothers). Numerical and categorical variables were analyzed using -tests/ANOVA -tests and Fisher’s exact tests, respectively. Results. Maternal HIV status at delivery was as follows: 69% positive and 24% unknown. Maternal factors significantly associated with newborn-triple therapy are Canadian origin, substance abuse, unstable housing, lost custody of previous children, and sex work. Neonatal factors are child protective services involvement, NICU, and lengthier admission. Maternal factors associated with monotherapy are African origin, HIV-positive, employment, and education. Further analysis based on maternal presentation at delivery demonstrated unequal distribution of many aforementioned factors. Discussion. This cohort revealed associations between particular factors and newborn-monotherapy or triple therapy that exist, suggesting that sociodemographic factors may influence the choice of ARV regimen. Canadian perinatal HIV transmission guidelines should qualify how to risk stratify newborns and consider use of rapid HIV antibody testing.Peer Reviewe

HIV Prophylaxis in High Risk Newborns: An Examination of Sociodemographic Factors in an Inner City Context

Background. Perinatal HIV transmission is less than 1% with antiretroviral (ARV) prophylaxis. Transmission risk appears higher in “high risk” dyads, yet this is not well defined, possibly exposing more infants to combination ARV compared with standard care. Objective. To describe characteristics of mother-infant dyads where infants received ARVs and how these characteristics relate to specific ARV regimens. Methods. Retrospective chart review of ARV-receiving newborns at St. Michael’s Hospital from 2007 to 2012 (and their mothers). Numerical and categorical variables were analyzed using t-tests/ANOVA F-tests and Fisher’s exact tests, respectively. Results. Maternal HIV status at delivery was as follows: 69% positive and 24% unknown. Maternal factors significantly associated with newborn-triple therapy are Canadian origin, substance abuse, unstable housing, lost custody of previous children, and sex work. Neonatal factors are child protective services involvement, NICU, and lengthier admission. Maternal factors associated with monotherapy are African origin, HIV-positive, employment, and education. Further analysis based on maternal presentation at delivery demonstrated unequal distribution of many aforementioned factors. Discussion. This cohort revealed associations between particular factors and newborn-monotherapy or triple therapy that exist, suggesting that sociodemographic factors may influence the choice of ARV regimen. Canadian perinatal HIV transmission guidelines should qualify how to risk stratify newborns and consider use of rapid HIV antibody testing

Herpes zoster in older adults in Ontario, 2002-2016: Investigating incidence and exploring equity.

Older adults are at increased risk of herpes zoster (HZ) and post-herpetic neuralgia (PHN) and HZ vaccines are available to help prevent infection. The objective of our study was to provide updated data on incidence of HZ and PHN related to clinical and demographic factors in older adults to inform immunization practices. We conducted a population-based, retrospective cohort study and included all cases of HZ seen in outpatient, emergency department, and hospital settings for adults aged 65 years and over between April 1, 2002 to August 31, 2016 in Ontario, Canada. We calculated the incidence of HZ and PHN, and estimated the proportion within each subgroup that developed PHN. We also assessed incidence by neighbourhood-level income quintile before and after the availability of vaccine for private purchase. The average annual incidence of HZ in any setting was 59.0 per 10,000 older adults, with higher incidence in outpatient as opposed to hospital settings. Incidence was higher in the oldest age groups, females, and those classified as immunocompromised or frail. Relative to the pre-vaccine era, the disparities in incidence of HZ by neighbourhood-level income increased, with higher rates of HZ and PHN seen in those residing in lower income quintiles. Additional prevention efforts should be targeted toward adults who are immunocompromised, frail, and those living in lower socioeconomic quintiles. Future work should assess the impact of the zoster vaccine program with a particular focus on equity in the publicly-funded era

Twenty Years of Medically-Attended Pediatric Varicella and Herpes Zoster in Ontario, Canada: A Population-Based Study

<div><p>Objective</p><p>To determine if reductions in medically-attended pediatric varicella and herpes zoster occurred in Ontario, Canada, after publicly-funded varicella immunization was implemented in 2004.</p><p>Methods</p><p>For fiscal years (FY) 1992-2011, we examined data on varicella and herpes zoster physician office visits, emergency department (ED) visits, hospitalizations (including for varicella-associated skin and soft tissue infections [SSTI]), and intensive care unit (ICU) admissions, among those aged <18 years. The pre-vaccine, privately-available, and vaccine program eras were FY1992-1998, FY1999-2003, and FY2004-2011, respectively. We used Poisson regressionand Kruskal-Wallis tests (all at the p<0.05 level of significance), and compared rates using incidence rate ratios (IRRs) and 95% confidence intervals (CIs).</p><p>Results</p><p>Incidence of varicella office visits declined over the study period from a high of 25.1/1,000 in FY1994 to a low of 3.2/1,000 in FY2011. ED visits and hospitalizations followed similar patterns of decreasing rates later in the study period. IRRs comparing the vaccine program versus pre-vaccine eras were 0.29 (95%CI: 0.26-0.32) for office visits, 0.29 (95%CI: 0.21-0.40) for ED visits, and 0.41 (95%CI: 0.10-1.69) for hospitalizations. Annual declines in varicella office visits were 7.7%, 9.1%, 8.4%, and 8.4% per year among children aged <1 year, 1-4 years, 5-11 years, and ≥12 years, respectively (all p<0.001). Age-specific rates of varicella-associated SSTI declined significantly among children <12 years (p<0.001) and rates of ICU admissions decreased significantly for children <1 year (p = 0.02). (p<0.001) over the study period. For children aged 5-17 years, herpes zoster office visits decreased whereas ED visits increased (both p<0.001) and there was a small, non-significant (p = 0.07), decrease in hospitalizations.</p><p>Conclusion</p><p>Medically-attended varicella decreased during the study period, particularly since varicella vaccine was publicly-funded. Results suggest immunization program-related changes in varicella epidemiology, including herd effects, demonstrated by reductions in varicella in program-ineligible age groups. We did not observe a consistent impact on herpes zoster.</p></div

Age-specific varicella physician office visits among Ontario children by fiscal year, 1992–2011.

<p>Age-specific varicella physician office visits among Ontario children by fiscal year, 1992–2011.</p