The current study demonstrates how actions regarding vaccination may have significant effects during an epidemic or pandemic. Earlier vaccination, increased compliance, and swifter vaccine administration can all blunt the overall population attack rate and save employers’ productivity. While vaccinating priority groups (including healthcare workers) and critical infrastructure workers can help mitigate the epidemic, neglecting other employees can miss potential gains in influenza mitigation. In fact, vaccinating nonpriority workers could help healthcare workers and critical infrastructure workers. These findings suggest that investing in mechanisms to accelerate vaccine administration, enhance compliance, and expedite vaccine availability among businesses could pay dividends to society and employers. Workplace vaccine education, awareness, and administration programs may be able to address each of these parameters.
The results emphasize the importance of large businesses in influenza transmission and vaccination plans. Even though a majority of employees belong to smaller firms (less than 10 employees), focusing vaccination efforts on just large firms could achieve the same results as trying to catch all of the businesses. This is potentially important since aiming to provide vaccine coverage to the myriad of small businesses can be a logistic challenge. Providing onsite vaccination to each small business may be difficult and unfeasible. Some small businesses may not have enough employees to stay open while their employees visit provider offices or public health clinics to get vaccinated. Many small businesses may not even have health insurance or adequate access to health care. The higher degree of social mixing that occurs in large firms appears to outweigh the sheer combined number of people in small businesses.
Another finding is that vaccination compliance rates do not need to be very high to mitigate the epidemic. Vaccinating only 20% of employees could still yield substantial benefits. In fact, there is little to gain from pushing employee vaccination compliance up to 50% or 100%. This has several implications. While employers may want to encourage or offer vaccination, they do not have to ensure that every individual in their workplaces get vaccinated. Additionally, achieving vaccination rates among working adults commensurate with seasonal influenza vaccination rates could be highly effective in quelling the epidemic.
Projecting the current results to the entire U.S. reveals the following:
- An unmitigated R0=1.3 epidemic would result in approximately a total of 45.5 million infected individuals and 23.8 million infected workers generating 39 million lost days of work and 4.9 billion in productivity losses. Vaccinating ACIP priority groups can save $4.4 billion in productivity. Vaccinating critical infrastructure workers can save an additional $70 million and the remainder of workers another $310 million.
- An unmitigated R0=1.6 epidemic would result in approximately a total of 77.7 million infected individuals and 39.0 million infected workers generating 63.9 million lost days of work and $8.0 billion in productivity losses. Vaccinating ACIP priority groups can potentially save in $6.5 billion in productivity. Vaccinating critical infrastructure workers may save an additional $376 million in productivity and the remainder of workers another $924 million.
Our study demonstrates the potential impact that an influenza epidemic may have. An influenza virus strain does not have to have high virulence (i.e., high hospitalization and fatality rates) to have a large effect on society. One should not overlook the potential tremendous impact of missed days from work. A seemingly “harmless” influenza strain that causes on average only 3–5 days of missed work for only half of the people who are symptomatic can generate large losses for employers.
All computer models are simplifications of reality and can never account for every possible factor or interaction. The model did not distinguish high-risk individuals, who may have much worse outcomes and therefore miss longer periods of work, from healthy individuals. An influenza pandemic and the resulting circumstances may not necessarily conform to the data and assumptions that the current model drew from referenced sources or previously published models and is limited to the DC metropolitan area. The model did not account for workdays missed by parents who have to take care of ill children. The model also did not capture decreased worker productivity associated with presenteeism.
In many ways, the current results may underestimate the economic effects of an epidemic. Losing large proportions of the labor force to illness may have significant negative externalities not captured by the model. Productivity losses do not necessarily scale linearly as assumed by the current model. Some firms may not be able to operate at all when certain crucial personnel are missing. Operational disruptions from labor force loss may have reverberating effects throughout society (e.g., losing a delivery service company will affect agriculture, manufacturing, health care). Additionally, some employers (e.g., self-insured employers as well as other employers who ultimately pay for costs borne by their contracted health plans) may have to bear the healthcare costs of their employees as well.
An unmitigated epidemic could result in substantial productivity losses (a mean of $112.6 million for the DC area for a 15% serologic attack rate and $193.8 million for a 25% serologic attack rate), even with the relatively low estimated mortality impact of H1N1. While vaccinating ACIP priority groups resulted in the largest savings, vaccinating remaining workers also captured additional savings. In fact, vaccinating remaining employees may provide additional savings for healthcare workers and critical infrastructure workers by reducing everyone’s chances of infection. Timely employee vaccination may play a crucial role in epidemic mitigation. While employee vaccination compliance affected the epidemic, once 20% compliance is achieved, additional increases in compliance provide limited additional benefit. Even though a vast majority of the workers are employed by small businesses, focusing on vaccinating larger firms may be just as effective in epidemic mitigation as trying to vaccinate employees in all of the workplaces.