Universal Mass Vaccination Programs Research Articles

Pneumonia hospitalizations of children aged

ABSTRACT As infection with Streptococcus pneumoniae is an important cause of pneumonia in children, the World Health Organization recommends childhood pneumococcal conjugate vaccines (PCVs). In January 2017, PCV universal mass vaccination (UMV) was introduced in Poland for children aged <2 years. The objective of this study was to estimate and describe the trends in the incidences of various types of pneumonia hospitalizations in Poland before (2013–2016) and after (2017–2018) introduction of the UMV program. The study was conducted at the regional hospitals of Opole and Bialystok and included all hospitalized children aged <2 years with a primary or secondary diagnosis of pneumonia in their electronic medical records. Pneumonia diagnoses were identified based on International Classification of Diseases 10th revision (ICD-10) codes for bacterial, viral, and other/unknown-cause pneumonias. The effect of the implementation of PCV UMV was modeled via an inferential multivariate model. Among 4,168 children included in the study, 64.3% were admitted before PCV UMV. The number of radiograph-confirmed likely bacterial pneumonia cases varied between 55 and 176 cases per 100,000 person-years, and no trend was observed over time. However, inferential modeling showed statistically significant decreasing trends in the incidence rates of bacterial-coded pneumonia (28.48%), viral-coded pneumonia (35.36%), all-cause pneumonia (24.60%), and radiograph-confirmed likely non-bacterial pneumonia (24.98%) among children eligible for UMV. This might be the first indication of the impact of the PCV UMV program in Poland.

34. Impact of Universal Mass Vaccination Programs of Children Against Hepatitis a with 2-dose and 1-dose Schedules: A Systematic Literature Review

BackgroundWith more than 100 million new hepatitis A (HepA) virus (HAV) infections estimated each year, HepA is a serious health concern worldwide. Several countries implemented 2- or 1-dose universal mass vaccination (UMV) programs of children with HAV vaccines. Here we present the first systematic review describing the impact of 2- and 1-dose UMV programs on HepA incidence and related health outcomes.MethodsWe systematically searched several databases for data published between Jan 2000–Jul 2019 (Figure 1). We assessed available evidence for 2- and 1-dose UMV programs with inactivated HAV vaccine in children worldwide, in terms of impact on HepA incidence, disease severity and mortality, vaccine efficacy, vaccine effectiveness and antibody persistence.Figure 1. PRISMA flowchart Results3739 articles were screened and 34 studies were included in our analysis (Figure 1). 18 real-world studies in 9 countries showed that HepA incidence declined in all ages following introduction of 2-dose and 1-dose UMV programs and persisted for at least 14 years (2-dose) and at least 6 years (1-dose) (Figure 2). Evidence for 1-dose schedule was limited to only 3 studies. HAV related outcomes (disease severity, mortality) decreased after UMV with either 2-dose or 1-dose schedule. Vaccine effectiveness for the 2-dose schedules was ≥ 95% over 3–5 years. Vaccine efficacy for the 1-dose schedule was > 98% over 0.1–7.5 years. Anti-HAV antibody persistence in vaccinated children was documented up to 15 years with ≥ 90% seropositivity rates for the 2-dose schedule and up to 10 years with ≥ 74.3% seropositivity rates for the 1-dose schedule. Anti-HAV antibody GMC data is presented in Table 1.Figure 2. Impact of vaccination on hepatitis A incidence in countries implementing 2-dose or 1-dose schedules (data from studies presenting ‘all ages’ incidence data) Table 1. Anti-HAV antibody GMCs following vaccination with 2-dose and 1-dose schedules, data from studies included in our reviewConclusionThe implementation of 2- and 1-dose UMV programs against HAV induced decreases in disease incidence and related outcomes. Experience with 2-dose schedule is extensive, with wide geographical use, while evidence beyond 10 years for the 1-dose schedule has not yet been demonstrated. Continued and robust surveillance is needed to monitor the epidemiology, vaccine effectiveness, antibody persistence and protection (particularly in the absence of natural boosting) in order to have a strong, scientifically sound basis for decision makers when concluding on HepA prevention strategies in their countries. Funding: GlaxoSmithKline Biologicals SADisclosures Anar Andani, BSc, GSK group of companies (Employee, Shareholder) Eveline M. Bunge, PhD, GSK group of companies (Research Grant or Support) Fernanda Salgado, MD, MSc, GSK group of companies (Employee) Rosa C. van Hoorn, MSc, GSK group of companies (Research Grant or Support) Bernard Hoet, MD, FFPM, GSK group of companies (Shareholder)

PIN13 Cost Minimization and Budget Impact Analysis of Pneumococcal Conjugated Vaccines in 3 Latin American Countries (2020-2024)

Countries in Latin America (LAC) introduced infant Pneumococcal Conjugated Vaccine (PCVs) immunization in their National Immunization Programs (NIPs) following the recommendation of the World Health Organization (WHO). Based on systematic literature reviews and expert opinions, WHO stated there is no evidence of a difference in the net impact of PCVs on overall disease burden, leaving concerns regarding the PCV choice. Therefore, we conducted a budget impact (BI) analysis of the use of PCV10 and PCV13 in Paraguay, Peru and Colombia to address the question of affordability. An excel-based cost calculator was used to estimate the BI of PCVs use in these countries between 2020 and 2024. We compared direct medical cost of the base case scenario (no-vaccine) with the post-vaccine introduction scenario to calculate the BI from the perspective of health care system. In addition, the BI comparing the use of PCV13 and PCV10 was also included. Vaccine prices and vaccine effects were obtained from published data of international organizations. The 5-years BI for PCV10 in Paraguay, Peru and Colombia was -33.3, 83.8 and 100.1 million of United States dollars (USD), respectively, and an incremental BI for PCV13 of 4.9, 14.8 and 21.4 million USD, respectively when compared with PCV10. The use of PCV10 in the NIP of Paraguay, Peru and Colombia will save 70.3, 31.8 and 46.1 million USD respectively in direct medical costs. The analysis found significant differences in the 5-years BI between PCV10 and PCV13, with more than 9 million USD incremental savings on treatments costs and 31.8 million USD incremental savings in vaccine costs for PCV10, in the analyzed countries. These findings can be used in budget planning and to maximize NIP budget. However, to sustain universal mass vaccination programs, policymakers should carefully consider the broader interaction among vaccines and socio-economic development.

Trends in all-cause pneumonia and otitis media in children aged

ABSTRACT In Colombia, pneumococcal conjugate vaccines (PCVs) were implemented into the infant universal mass vaccination program in a stepwise manner; PCV-7 between 2009 and 2011 in different geographic regions/cities, with nationwide introduction of a 10-valent vaccine (PHiD-CV) in 2012. We aimed to describe trends in all-cause pneumonia mortality and overall mortality, and in the incidence of all-cause pneumonia and otitis media (OM) in Colombian children <2 y (y = years) of age, before and after PCV introduction. We obtained mortality and incidence data, nationally and for five major cities (Bogota, Medellin, Barranquilla, Cali and Cartagena) from 2005–2016 and 2008–2016, respectively, comparing mortality and incidence proportions in the post-PCV introduction period with those in the pre-PCV period. Overall mean reductions in all-cause pneumonia mortality was observed in the post-PCV period nationally (48.8%; 95%CI: 45.5–51.8%) and in four cities including Bogota (77.1%; 71.1–81.8%) and Medellin (56.4%; 44.1–65.9%); no substantial reduction was observed in Cartagena. Similar findings were observed for overall mortality. Reductions in all-cause pneumonia incidence were observed in Bogota (66.0%; 65.5–66.6%), Medellin (40.6%; 39.3–41.9%) and Cartagena (15.0%; 11.2–18.6%), while incidence increased in Barranquilla (78.5%; 68.4–89.2%) and Cali (125.5%; 119.2–132.0%). All-cause OM incidence fell in Medellin and Bogota (42.1–51.1%) but increased (95.8%) in Barranquilla. In conclusion, overall reductions in disease outcomes were observed following PCV introduction in most cities and nationwide. Decreasing trends in outcomes were observed prior to PCV introduction, and limited data points and data reporting issues may have influenced our results. (ClinicalTrials.gov: NCT02567747)

Cost-effectiveness evaluation of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine for children in Taiwan

BackgroundStreptococcus pneumoniae (S. pneumoniae) and non-typeable Haemophilus influenzae (NTHi) are substantial contributors to morbidity and mortality of diseases including invasive pneumococcal diseases (IPDs), pneumonia and acute otitis media (AOM) worldwide. In Taiwan, 10-valent pneumococcal polysaccharide and NTHi protein D conjugate vaccine (PHiD-CV) and 13-valent pneumococcal conjugate vaccine (PCV13) are licensed in children against pneumococcal disease. In addition to S. pneumoniae, clinical trials suggest efficacy of PHiD-CV against NTHi AOM. This study aims at evaluating the cost-effectiveness of a 2 + 1 schedule of PHiD-CV vs. PCV13 2 + 1 in the universal mass vaccination program of infants in Taiwan.MethodsA published Markov cohort model was adapted to simulate the epidemiological burden of IPD, pneumonia and AOM for a birth cohort in Taiwan over 10 years. The probability of entering a specific health state was based on the incidence rate of the diseases. Only direct medical costs were included, and costs and outcomes were discounted annually. Vaccine efficacy assumptions were based on published data and validated by a panel of independent experts. Clinical, epidemiological, and serotype distribution data were based on locally published data or the National Health Insurance Research Database. Price parity of vaccines was assumed. Published pneumococcal disease-related disutility weights were used due to lack of local data. Incremental cost-effectiveness ratio was calculated and benchmarked against the recommended threshold in Taiwan. Extensive one-way sensitivity analysis, alternative scenarios and probabilistic sensitivity analysis were performed to test the robustness of the results.ResultsPHiD-CV would potentially reduce the number of NTHi-related AOM cases substantially and prevent comparable IPD and pneumonia-related cases and deaths compared to PCV13. Over a 10-year horizon, PHiD-CV is estimated to dominate PCV13, saving 8.8 million New Taiwan Dollars (NTD) and saving 21 quality-adjusted life years. The result was robust over a wide range of sensitivity analyses. The dominance of PHiD-CV was demonstrated in 61% of the simulations.ConclusionsPHiD-CV 2 + 1 would provide comparable prevention of IPD, pneumonia cases and additional reduction of NTHi-AOM cases, and is considered dominant compared with PCV13 2 + 1 in Taiwan.

Pneumococcal disease mortality in children < 5 years of age after pneumococcal conjugate vaccine introduction in colombia: a time-trend analysis, 2005-2016

Background: Pneumonia has been one of leading causes of childhood mortality in Colombia. Since 2006, the Colombian Ministry of Health recommends pneumococcal conjugate vaccine (PCV) to high-risk groups. The universal mass vaccination program was fully implemented in 2011 (2-4-12-month schedule). In 2012, Pneumococcal polysaccharide protein D-conjugate vaccine replaced the use of 7-valent PCV. The aim of the current study is to describe trends in pneumonia-related mortality in Colombian children, before and after the introduction of the PCV program.

Cost-effectiveness analysis of a universal mass vaccination program with a PHiD-CV 2+1 schedule in Malaysia

BackgroundCurrently, two pediatric pneumococcal conjugate vaccines are available in the private market of Malaysia—13-valent pneumococcal conjugate vaccine (PCV13) and pneumococcal polysaccharide and non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV). This study aimed to evaluate the cost-effectiveness of a universal mass vaccination program with a PHiD-CV 2+1 schedule versus no vaccination or with a PCV13 2+1 schedule in Malaysia.MethodsA published Markov cohort model was adapted to evaluate the epidemiological and economic consequences of programs with no vaccination, a PHiD-CV 2+1 schedule or a PCV13 2+1 schedule over a 10-year time horizon. Disease cases, deaths, direct medical costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) were estimated. Locally published epidemiology and cost data were used whenever possible. Vaccine effectiveness and disutility data were based on the best available published data. All data inputs and assumptions were validated by local clinical and health economics experts. Analyses were conducted from the perspective of the Malaysian government for a birth cohort of 508,774. Costs and QALYs were discounted at 3% per annum. One-way and probabilistic sensitivity analyses were performed.ResultsCompared with no vaccination, a PHiD-CV 2+1 program was projected to prevent 1109 invasive pneumococcal disease (IPD), 24,679 pneumonia and 72,940 acute otitis media (AOM) cases and 103 IPD/pneumonia deaths over 10 years, with additional costs and QALYs of United States dollars (USD) 30.9 million and 1084 QALYs, respectively, at an ICER of USD 28,497/QALY. Compared with a PCV13 2+1 program, PHiD-CV 2+1 was projected to result in similar reductions in IPD cases (40 cases more) but significantly fewer AOM cases (30,001 cases less), with cost savings and additional QALYs gained of USD 5.2 million and 116 QALYs, respectively, demonstrating dominance over PCV13. Results were robust to variations in one-way and probabilistic sensitivity analyses.ConclusionsA PHiD-CV 2+1 universal mass vaccination program could substantially reduce pneumococcal disease burden versus no vaccination, and was expected to be cost-effective in Malaysia. A PHiD-CV 2+1 program was also expected to be a dominant choice over a PCV13 2+1 program in Malaysia.

Seroprevalence and clinical characteristics of viral hepatitis in transfusion-dependent thalassemia and hemophilia patients.

Background/AimsTransfusion dependent subjects are at a great risk of viral hepatitis infection. We aimed to evaluate the prevalence and factors associated with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection among transfusion-dependent patients in Taiwan.MethodsA total of 140 patients (67 thalassemic patients, 70 hemophilic patients, two patients with hereditary spherocytosis and one patient with von Willebrand disease) were prospectively enrolled to evaluate the prevalence and factors associated with viral hepatitis and spontaneous HCV clearance. All patients were tested for HBV and HCV serology and virology. Two consecutive serum samples, at least 1 year apart, were collected to clarify HCV seroclearance.ResultsThe seropositivity rate of hepatitis B surface antigen (HBsAg), HCV antibody (anti-HCV), and both HBsAg/anti-HCV were 6.4%, 45.7% and 5%, respectively. Logistic regression analysis of factors associated with anti-HCV seropositivity included age (odds ratio/95% confidence interval [OR/CI]: 1.12/1.07–1.18, P<0.001), serum alanine aminotransferase (ALT) (OR/CI: 1.04/1.02–1.06, P<0.001) and platelet counts (OR/CI: 0.995/0.991–0.998, P = 0.002). Age was the only factor independently associated with HBsAg seropositivity (OR/CI: 1.08/1.02–1.14.4, P = 0.007). Compared to patients born before 1992, the seroprevalence of HCV among thalassemic patients decreased dramatically in those born after 1992 (46.0% vs. 11.8%, p = 0.012). The seroprevalence of HCV among hemophilic patients also decreased significantly when comparing patients born before 1987 to those born after 1987 (79.5% vs. 11.5%, p<0.001). Similarly, the seroprevalence of HBV decreased significantly in the post-vaccination cohort compared to its counterpart (13.1%, vs. 1.3%, p = 0.005). The spontaneous clearance of HCV was observed in 25.4% (15/59) of patients, and ALT was the only factor associated with it (OR/CI 0.98/0.96–1.00, P = 0.02).ConclusionsBoth HBV and HCV infections are prevalent among transfusion-dependent thalassemic and hemophilic patients in Taiwan. Nevertheless, seroprevalence decreased significantly and dramatically for HCV after universal blood screening and for HBV after implementation of a universal mass vaccination program.

Cost-Effectiveness Analysis of Pneumococcal Vaccination with the Pneumococcal Polysaccharide NTHi Protein D Conjugate Vaccine in the Philippines

ObjectivesTo compare the cost-effectiveness of a universal mass vaccination (UMV) program with a 2 + 1 schedule of a 10-valent pneumococcal polysaccharide nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) against two strategies: 1) a no-vaccination strategy and 2) a pneumococcal 13-valent conjugate vaccine (PCV13) 2 + 1 strategy in the Philippines. MethodsA published Markov cohort model was adapted to simulate the epidemiological and economic burden of pneumococcal diseases (meningitis, bacteremia, pneumonia, and acute otitis media) within a projected birth cohort in 2012 of 1,812,137 newborns over lifetime. Analyses were conducted at an annual discount rate of 5% from the perspective of the Philippine government. The current evaluation was updated with the best available local/regional clinical epidemiological data and published efficacy evidence. ResultsCompared with the no-vaccination strategy, the PHiD-CV 2 + 1 UMV program was projected to prevent 3,343 deaths due to invasive pneumococcal diseases and pneumonia and 326,862 cases of pneumococcal diseases, resulting in an incremental cost-effectiveness ratio of 50,913 pesos/quality-adjusted life-year gained, which was considered to be highly cost-effective according to the threshold recommended by the World Health Organization. In comparison with the PCV13 2 + 1 strategy, the PHiD-CV 2 + 1 strategy was estimated to have a substantial reduction in acute otitis media (127,680 cases) and therefore a cost saving of potential 92.5 million pesos assuming price parity between PHiD-CV and PCV13 (US $1 = 42.13 pesos in 2012). ConclusionsThe PHiD-CV 2 + 1 UMV program is projected to be cost-effective, compared with no vaccination, and would provide substantial savings with higher quality-adjusted life-year gains as compared with the PCV13 2 + 1 strategy in the context of the Philippines.

Sustained low hospitalization rates after four years of rotavirus mass vaccination in Austria

This hospital based surveillance study evaluates the effects of the rotavirus mass vaccination program, which was initiated in Austria in August 2007. Since then, incidence rates of rotavirus hospitalizations in children <15 years of age have decreased by 70% and 64% in 2010 and 2011 compared to the pre-vaccination era (2001–2005). Incidence rates were highest in children <90 days of age, highlighting the importance of the early start of active rotavirus immunization. In children between 2 and 3.5 years in 2011, who were in the second and third year after vaccination in the universal mass vaccination program, incidence rates remained low suggesting sustained protection after vaccination up to three years. In the years 2010 and 2011, field effectiveness of the vaccines was between 79% and 96%, depending on the assumptions made for children without information on vaccination history. From genotyping an increase of the prevalence of G2P[4] in children with breakthrough infection (disease despite vaccination) can be suspected. The rate of severe adverse events was 1.3–1.5 per 10−5 administered doses of rotavirus vaccines and no death, intussusception or Kawasaki disease was reported in 2010 and 2011 following rotavirus vaccination.

Group A rotavirus universal mass vaccination: how and to what extent will selective pressure influence prevalence of rotavirus genotypes?

Two human group A rotavirus (RVA) vaccines are available and highly effective in preventing severe gastroenteritis caused by all commonly circulating human RVA genotypes. The effect of universal mass vaccination on the RVA genotype distribution is discussed based on the knowledge of complete RVA genotype constellations, data from clinical efficacy trials and effectiveness studies, and genotype surveillance data from countries with universal mass vaccination programs. The theoretically predicted relative enrichment of RVA strains with the G2P[4] DS-1-like genotype constellation in regions with high coverage by Rotarix® (GlaxoSmithKline Biologicals, Rixensart, Belgium) seems to become apparent. A G3P[8] genotype increase, which was noted in several regions with a high coverage of RotaTeq® (Merck and Co., Inc., NJ, USA), is more difficult to explain based on the theoretical considerations.

Streptococcus pneumoniae serotype 19A in Latin America and the Caribbean: a systematic review and meta-analysis, 1990-2010.

BackgroundPneumococcal conjugate vaccines (PCVs) are in the process of implementation in Latin America. Experience in developed countries has shown that they reduce the incidence of invasive and non-invasive disease. However, there is evidence that the introduction of PCVs in universal mass vaccination programs, combined with inappropriate and extensive use of antibiotics, could be associated to changes in non-PCV serotypes, including serotype 19A. We conducted a systematic review to determine the distribution of serotype 19A, burden of pneumococcal disease and antibiotic resistance in the region.MethodsWe performed a systematic review of serotype 19A data from observational and randomized clinical studies in the region, conducted between 1990 and 2010, for children under 6 years. Pooled prevalence estimates from surveillance activities with confidence intervals were calculated.ResultsWe included 100 studies in 22 countries and extracted data from 63. These data reported 19733 serotyped invasive pneumococcal isolates, 3.8% of which were serotype 19A. Serotype 19A isolates were responsible for 2.4% acute otitis media episodes, and accounted for 4.1% and 4.4% of 4,380 nasopharyngeal isolates from healthy children and in hospital-based/sick children, respectively. This serotype was stable over the twenty years of surveillance in the region. A total of 53.7% Spn19A isolates from meningitis cases and only 14% from non meningitis were resistant to penicillin.ConclusionsBefore widespread PCV implementation in this region, serotype 19A was responsible for a relatively small number of pneumococcal disease cases. With increased use of PCVs and a greater number of serotypes included, monitoring S. pneumoniae serotype distribution will be essential for understanding the epidemiology of pneumococcal disease.

Herd immunity after two years of the universal mass vaccination program against rotavirus gastroenteritis in Austria

Austria was the first country in Europe implementing a universal mass vaccination program against rotavirus gastroenteritis (RV-GE) for all infants nationwide. Epidemiological data from a hospital based surveillance system show that incidence rates of children hospitalized with RV-GE decreased in 2009 compared to 2008 and compared to the prevaccination period 2001–2005. Decreasing hospitalization-rates from RV-GE were observed in children of all age groups, even in those not eligible for vaccination according to their age, suggesting herd immunity induced by universal mass vaccination against RV-GE. In 2009 the disease burden was highest in children below three months of age stressing the importance of the early start of the immunization course.

Universal Mass Vaccination Against Rotavirus Gastroenteritis

Since July 2007, rotavirus vaccinations have been subsidized in Austria for all children from the seventh week up to the sixth month of life. Vaccination coverage over the whole period was 72% with an increase to 87% in 2008. In a sentinel network including 11 pediatric hospital wards in Austria, data of children up to 15 years of age and hospitalized due to rotavirus gastroenteritis between January 2001 and December 2008 have been collected. The hospitalization rates of children up to 12 months of age with rotavirus gastroenteritis were 2066 x 10(-5) between 2001 and 2006 and decreased to 631 x 10(-5) in 2008. For children between 12 and 24 months of age the hospitalization rate decreased from 1822 x 10(-5) (2001-2006) to 1456 x 10(-5) in 2008. In children aged 2 to less than 5 years, incidence rates were 436 x10(-5) (2001-2006) and 461 x 10(-5) in 2008. In older children, the hospitalization rates remained unchanged. In the target population for the RV-vaccine, a decrease of hospitalization rates due to rotavirus gastroenteritis of 74% was observed compared to the era before the introduction of the vaccine. The field effectiveness of the vaccine was estimated between 61% and 98%, depending on assumptions about the vaccination status. Within 18 months, the universal mass vaccination program against rotavirus led to a substantial decrease in the hospitalization rates of the target cohort of the immunization program in Austria.

Seroprevalence of Hepatitis A Infection in the Turkish Republic of Northern Cyprus

Aims: This study was conducted to determine the seroprevalence of hepatitis A virus (HAV) infection in the Turkish Republic of Northern Cyprus. Materials and Methods: A total of 660 unvaccinated persons 1 to 30 years old were selected for the study with cluster sampling. Information on sociodemographic characteristics was gathered for each participant and, in 641 of them, anti-HAV antibodies were assayed using an enzyme immune assay. Results: Anti-HAV prevalence in the Turkish population under the age of 30 in Northern Cyprus was 23.9%. For the age groups 1-5, 6-10 and 11-15 years, seroprevalence rates were relatively low (11.4, 9.4 and 12%, respectively). For age groups 16 years and over, HAV seroprevalence gradually increased with age, rising to 30.4% in 16 to 20 years and to 52.5% in 21 to 30 years of age. In addition to age, other variables significantly associated with HAV seroprevalence included low family income, family size, waste water sewage, and the education level of parents. Conclusions: Anti-HAV seroprevalence in the Turkish Republic of Northern Cyprus shows an intermediate prevalence. As well as expanding health education and improving sanitation, a hepatitis A universal mass vaccination program would be logical for the population.

Sixteen Years of Global Experience with the First Refrigerator-Stable Varicella Vaccine (Varilrix™)

Without vaccination, chickenpox (varicella) will affect almost every person in the world during their lifetime. The burden of disease due to varicella is often unrecognized. Varilrix is a varicella vaccine derived from the Oka strain of varicella virus. The vaccine, as a frozen formulation, was licensed for use in 1984 and was the first commercially available varicella vaccine. It subsequently became the first refrigerator-stable varicella vaccine; its development commenced in 1991 and it has been licensed for use since 1994. Varilrix is indicated for use in high-risk groups, potentially immunocompromised individuals, and healthy subjects in many countries. This article reviews data from extensive worldwide experience with the refrigerator-stable version of the vaccine, including information derived from its use in over 10,000 individuals participating in clinical trials investigating its immunogenicity, efficacy, effectiveness, and safety, as well as postmarketing data including its use in universal mass vaccination programs. Sixteen years of clinical and postmarketing experience with the same formulation represents the longest and most extensive experience with a refrigerator-stable varicella vaccine worldwide. Varilrix, in conjunction with the trivalent measles-mumps-rubella vaccine Priorix, has also been the basis for clinical development of the tetravalent measles-mumps-rubella-varicella vaccine (Priorix-Tetra).

Risk Factors for Severe Rotavirus Gastroenteritis

Background: Rotavirus remains a common cause of hospitalization for acute gastroenteritis in the developed world. In general, rotavirus gastroenteritis (RVGE) occurs in previously healthy children, but there may also be certain definable risk factors associated with development of severe disease. Method: A systematic literature search was performed to examine data on risk factors for severe RVGE and to describe the inconsistencies which continue to emerge in this field. Results: Although some social risk factors were identified, including socio-economic disadvantage, they are too widespread among European populations for prevention measures to be focused on certain infant groups. Physical risk factors identified include being born prematurely, having low (1.5–2.49 kg) birth weight, requirement for neonatal intensive care facilities, malnutrition, and immunodeficiency. Rotavirus infection may also exacerbate the progression or outcome of other conditions, for example, celiac disease, acquired immunodeficiency, or renal complications, thus strengthening the case for vaccination to prevent RVGE in these patient groups. Conclusions: Universal mass vaccination programs, which do not discriminate between populations, would seem to be the most appropriate approach to controlling the burden of rotavirus disease.