American Journal of Preventive Medicine - Articles in Press

A Computer Simulation of Employee Vaccination to Mitigate an Influenza Epidemic - Corrected Proof

2009-12-31

Background:: Better understanding the possible effects of vaccinating employees is important and can help policymakers and businesses plan vaccine distribution and administration logistics, especially with the current H1N1 influenza vaccine in short supply.Purpose: This article aims to determine the effects of varying vaccine coverage, compliance, administration rates, prioritization, and timing among employees during an influenza pandemic.Methods: As part of the H1N1 influenza planning efforts of the Models of Infectious Disease Agent Study network, an agent-based computer simulation model was developed for the Washington DC metropolitan region, encompassing five metropolitan statistical areas. Each simulation run involved introducing 100 infectious individuals to initiate a 1.3 reproductive-rate (R0) epidemic, consistent with H1N1 parameters to date. Another set of scenarios represented a R0=1.6 epidemic.Results: An unmitigated epidemic resulted in substantial productivity losses (a mean of $112.6 million for a serologic 15% attack rate and $193.8 million for a serologic 25% attack rate), even with the relatively low estimated mortality impact of H1N1. Although vaccinating Advisory Committee on Immunization Practices–defined priority groups resulted in the largest savings, vaccinating all remaining workers captured additional savings and, in fact, reduced healthcare workers' and critical infrastructure workers' chances of infection. Moreover, although employee vaccination compliance affected the epidemic, once 20% compliance was achieved, additional increases in compliance provided less incremental benefit. Even though a vast majority of the workplaces in the DC metropolitan region had fewer than 100 employees, focusing on vaccinating only those in larger firms (≥100 employees) was just as effective in mitigating the epidemic as trying to vaccinate employees in all workplaces.Conclusions: Timely vaccination of at least 20% of the large-company workforce can play an important role in epidemic mitigation.

Improving Influenza Vaccination Rates in the Workplace: A Randomized Trial - Corrected Proof

2009-12-25

Background: To minimize absenteeism resulting from influenza, employers frequently offer on-site influenza vaccination to employees. Yet the level of uptake of vaccine is low among working adults. This study was designed to increase workplace influenza vaccination rates by offering both a choice of intranasal (LAIV) and injectable (TIV) influenza vaccines to eligible employees, and an incentive for being vaccinated, and by increasing awareness of the vaccine clinic.Design: This study used a stratified randomized cluster trial.Setting/participants: A total of 12,222 employees in 53 U.S. companies with previous influenza vaccine clinics were examined.Interventions: Control sites advertised and offered vaccine clinics as previously done. Choice sites offered LAIV or TIV and maintained their previous advertising level but promoted the choice of vaccines. Choice Plus sites increased advertising and promoted and offered a choice of vaccines and a nominal incentive.Main outcome measures: These included vaccination rates among eligible employees. Hierarchic linear modeling (HLM) was used to determine factors associated with vaccination.Results: The overall vaccination rate increased from 39% in 2007–2008 to 46% in 2008–2009 (p<0.001). The difference in vaccination rates for LAIV was 6.5% for Choice versus Control and 9.9% for Choice Plus versus Control (both p<0.001). Rates of TIV increased by 15.9 percentage points in the Choice Plus arm versus Control for workers aged ≥50 years (p=0.024). Rates of TIV did not change in workers aged 18–49 years in either intervention arm or in workers aged ≥50 years in the Choice arm. In HLM analyses, factors significantly associated with increased vaccination were older age, female gender, previous company vaccination rate, and the Choice Plus intervention.Conclusions: An incentive for vaccination, an intensified advertising campaign, and offering a choice of influenza vaccines improved vaccination rates in the workplace.