Impact of the introduction of pneumococcal conjugate vaccine on immunization coverage among infants

The composition of demand for newly launched vaccines: results from the pneumococcal and rotavirus vaccine introductions in Ethiopia and Malawi

Understanding post-launch demand for new vaccines can help countries maximize the benefits of immunization programmes. In particular, low- and middle-income countries (LMICs) should ensure adequate resource planning with regards to stock consumption and service delivery for new vaccines, whereas global suppliers must produce enough vaccines to meet demand. If a country underestimates the number of children seeking vaccination, a stock-out of commodities will create missed opportunities for saving lives. We describe the post-launch demand for the first dose of pneumococcal conjugate vaccine (PCV1) in Ethiopia and Malawi and the first dose of rotavirus vaccine (Rota1) in Malawi, with focus on the new birth cohort and the ‘backlog cohort’, comprised of older children who are still eligible for vaccination at the time of launch. PCV1 and Rota1 uptake were compared with the demand for the first dose of pentavalent vaccine (Penta1), a routine immunization that targets the same age group and immunization schedule. In the first year, the total demand for PCV1 was 37% greater than that of Penta1 in Ethiopia and 59% greater in Malawi. In the first 6 months, the demand of Rota1 was only 5.9% greater than Penta1 demand in Malawi. Over the first three post-introduction months, 70.7% of PCV1 demand in Ethiopia and 71.5% of demand in Malawi came from children in the backlog cohort, whereas only 28.0% of Rota1 demand in Malawi was from the backlog cohort. The composition of demand was impacted by time elapsed since vaccine introduction and age restrictions. Evidence suggests that countries’ plans should account for the impact of backlog demand, especially in the first 3 months post-introduction. LMICs should request for higher stock volumes when compared with routine needs, plan social mobilization activities to reach the backlog cohort and allocate human resources and cold chain capacity to accommodate high demand following vaccine introduction.

Vaccination coverage levels among children enrolled in the Vaccine Safety Datalink

INTRODUCTION

The Vaccine Safety Datalink (VSD) is a collaborative project whose infrastructure provides comprehensive medical and immunization histories for more than 9 million adults and children annually, a predominantly insured population. This study provides the coverage rates of recommended vaccines among children 19-35 months in the VSD from 2005 through 2010. We examine the consistency in vaccine coverage levels, detect possible trends, and evaluate any effect of vaccine shortages on coverage in the VSD.

METHODS

We included data from all 10 VSD sites, and examined each year independently. Coverage rates were defined as the percentage of children in the VSD aged 19, 24, or 35 months in a given study year who had received the specified Advisory Committee on Immunization Practices (ACIP) recommended vaccine(s).

RESULTS

We assessed coverage on 658,154 children. The overall coverage rate for children receiving all of the specified ACIP recommended vaccines was 73%, 80%, and 78% at ages 19, 24, and 35 months respectively. The range of coverage across all ages and years was 95-97% for polio vaccine, 91-97%, for MMR vaccine, 94-97% for HepB vaccine, 81-95% for DTaP vaccine, 90-95% for varicella vaccine, 66-91% for PCV, and 93-98% for Hib vaccine. Coverage rates of 4 or more doses of PCV were relatively low in 2005 possibly due to a vaccine shortage, and increased sharply in 2007. Hib vaccine coverage was relatively stable among all ages until 2009 when rates declined among children aged 19 and 24 months also during a vaccine shortage.

CONCLUSIONS

Vaccine coverage in the VSD is high, but there is a decline from 2005 to 2010. The results of this study provide benchmark data for future studies, and describe how vaccine supply shortages and resulting changes in ACIP recommendations may have affected vaccine coverage rates in the VSD.

The Vaccine Safety Datalink: a model for monitoring immunization safety

The Vaccine Safety Datalink (VSD) project is a collaborative project between the Centers for Disease Control and Prevention and 8 managed care organizations (MCOs) in the United States. Established in 1990 to conduct postmarketing evaluations of vaccine safety, the project has created an infrastructure that allows for high-quality research and surveillance. The 8 participating MCOs comprise a large population of 8.8 million members annually (3% of the US population), which enables researchers to conduct studies that assess adverse events after immunization. Each MCO prepares computerized data files by using a standardized data dictionary containing demographic and medical information on its members, such as age and gender, health plan enrollment, vaccinations, hospitalizations, outpatient clinic visits, emergency department visits, urgent care visits, and mortality data, as well as additional birth information (eg, birth weight) when available. Other information sources, such as medical chart review, member surveys, and pharmacy, laboratory, and radiology data, are often used in VSD studies to validate outcomes and vaccination data. Since 2000, the VSD has undergone significant changes including an increase in the number of participating MCOs and enrolled population, changes in data-collection procedures, the creation of near real-time data files, and the development of near real-time postmarketing surveillance for newly licensed vaccines or changes in vaccine recommendations. Recognized as an important resource in vaccine safety, the VSD is working toward increasing transparency through data-sharing and external input. With its recent enhancements, the VSD provides scientific expertise, continues to develop innovative approaches for vaccine-safety research, and may serve as a model for other patient safety collaborative research projects.

Trends in otitis media treatment failure and relapse

OBJECTIVES

The goals were to describe trends in acute otitis media, treatment failure, and relapse and in high-dose amoxicillin use and to determine whether treatment of acute otitis media with high-dose amoxicillin was associated with treatment failure or relapse.

METHODS

We conducted a retrospective study of acute otitis media visits made between 1996 and 2004 by children 2 months to 12 years of age in a large group practice, using computerized data. We defined acute otitis media as an otitis media visit with antibiotics dispensed (preceded by 30 days without otitis media visits), treatment failure as initiation of treatment with a second antibiotic before the first prescription was finished, and relapse as initiation of antibiotic treatment after the first prescription was finished but within 30 days after the index acute otitis media episode. The primary independent measure was high-dose amoxicillin (>70 mg/kg per day). We evaluated changes over time and determined whether high-dose amoxicillin use was associated with otitis media treatment failure or relapse.

RESULTS

We identified 111,335 acute otitis media visits over a 9-year period. The incidence of acute otitis media decreased from 385.1 visits per 1000 enrollees in 1996 to 188.8 visits per 1000 enrollees in 2004. The proportion of acute otitis media visits treated with high-dose amoxicillin increased from 1.7% in 1996 to 41.9% in 2004. Both otitis media treatment failure and relapse rates decreased from 1996 to 2004 (from 3.9% to 2.6% and from 9.2% to 8.9%, respectively). The odds of treatment failure or relapse did not differ between acute otitis media episodes treated with high-dose and low-dose amoxicillin.

CONCLUSIONS

During the past decade, acute otitis media, treatment failure, and relapse became less common and high-dose amoxicillin use increased. However, high-dose amoxicillin treatment did not reduce the risk of individual infections resulting in adverse outcomes.