1475. Impact of a Routine Infant PCV Program on the Serotype Distribution of Episodes of Invasive Pneumococcal Disease (IPD) and Non-bacteremic Pneumococcal Pneumonia in Adults

Background Herd immunity from pediatric pneumococcal conjugate vaccine (PCV) programs has resulted in substantial reductions in IPD due to PCV serotypes (ST). We assessed whether similar changes in ST distribution occur in non-bacteremic pneumococcal pneumonia (NBPP). Methods The Toronto Invasive Bacterial Diseases Network performs population-based surveillance for IPD and hospitalized, culture-confirmed NBPP in Toronto/Peel Region, Canada (Pop 4.5M). Patient data are collected by interview/chart review; illness associated with respiratory isolates is categorized using Musher criteria. Results Since 2002, 6627 episodes of IPD, and 7323 non-bacteremic episodes with a respiratory isolate of S. pneumoniae (2180 meeting modified Musher criteria for NBPP) have occurred in adults. Distributions of vaccine-type serotypes in IPD and NBPP pre-PCV7 (2002-2004), post-PCV7 (2006-2009) and late post-PCV13 (2014-2019) are shown in the Figure. There were no significant changes in distribution of vaccine serotype groups from 2014-2019 in IPD or NBPP. From 2014-2019, serotypes included in PCV13 and PCV20 were associated with 33% and 59% of IPD cases, and 29% and 49% of NBPP cases in adults.. Figure. distribution of serotype groups included in different pneumococcal vaccines in cases of IPD and non-bacteremic pneumonia Conclusion Eight years post routine infant PCV13 implementation, PCV13 type IPD and NBPP persists in adults. The distribution of vaccine-type strains is similar in IPD and NBPP; although non-vaccine-type strains are more common in NBPP. Disclosures Allison McGeer, MD, FRCPC, GlaxoSmithKline (Advisor or Review Panel member, Research Grant or Support)Merck (Advisor or Review Panel member, Research Grant or Support)Pfizer (Research Grant or Support)

The efficiency of routine infant immunization services in six countries: a comparison of methods

Background Few studies have systematically examined the efficiency of routine infant immunization services. Using a representative sample of infant immunization sites in Benin, Ghana, Honduras, Moldova, Uganda and Zambia (316 total), we estimated average efficiency levels and variation in efficiency within each country, and investigated the properties of published efficiency estimation techniques. Methods Using a dataset describing 316 immunization sites we estimated site-level efficiency using Data Envelopment Analysis (DEA), Stochastic Frontier Analysis (SFA), and a published ensemble method combining these two approaches. For these three methods we operationalized efficiency using the Sheppard input efficiency measure, which is bounded in (0, 1), with higher values indicating greater efficiency. We also compared these methods to a simple regression approach, which used residuals from a conventional production function as a simplified efficiency index. Inputs were site-level service delivery costs (excluding vaccines) and outputs were total clients receiving DTP3. We analyzed each country separately, and conducted sensitivity analysis for different input/output combinations. Results Using DEA, average input efficiency ranged from 0.40 in Ghana and Moldova to 0.58 in Benin. Using SFA, average input efficiency ranged from 0.43 in Ghana to 0.69 in Moldova. Within each country scores varied widely, with standard deviation of 0.18–0.23 for DEA and 0.10–0.20 for SFA. Input efficiency estimates generated using SFA were systematically higher than for DEA, and the rank correlation between scores ranged between 0.56–0.79. Average input efficiency from the ensemble estimator ranged between 0.41–0.61 across countries, and was highly correlated with the simplified efficiency index (rank correlation 0.81–0.92) as well as the DEA and SFA estimates. Conclusions Results imply costs could be 30–60% lower for fully efficient sites. Such efficiency gains are unlikely to be achievable in practice – some of the apparent inefficiency may reflect measurement errors, or unmodifiable differences in the operating environment. However, adapted to work with routine reporting data and simplified methods, efficiency analysis could triage low performing sites for greater management attention, or identify more efficient sites as models for other facilities.

Over-diagnosis of Rotavirus Infection in Infants Due to Detection of Vaccine Virus

An accurate rotavirus diagnosis is important for clinical management and monitoring active disease and vaccine effectiveness. Between 2016–2018, rotavirus-positive results in our laboratory were from vaccine virus shedding in 71/152 (46.7%) infants with a request for rotavirus testing. Routine infant diagnostic testing should ideally distinguish vaccine from wild-type viruses.