Industry Insight

Joaquin Mould: RWE allows us to evaluate influenza vaccine effectiveness on a continual basis and provides an ever-growing data set to evaluate real-world outcomes, offering larger, more diverse populations of patients and healthcare settings. In addition, RWE using claims databases allows us to compare direct medical costs with real vaccinated subjects, so we are able to estimate the level of protection from the vaccines as well as measure the economic impact (savings) in a direct and more credible way. The latter, as an example, compares to regular epi or cost-effectiveness models that include a large number of assumptions and high levels of uncertainties. With RWE economic analyses, we can estimate real cost differences by assessing real subjects and their claims. In influenza, with RWE you may not only estimate the proportion of influenza-related hospitalisations or outpatient visits, but also the mean costs for influenza-related hospitalisations or average costs for ambulatory and pharmacy services, per influenza vaccine type.

As the inf luenza viruses change, so does the burden of disease. In the US, it’s estimated that there have been 140,000-710,000 hospitalisations and 12,000-52,000 deaths annually between 2010 and 2020, all of which come with associated healthcare costs and economic burden. Because the circulating strains of inf luenza virus can change from year to year, annual reformulation and revaccination are necessary to help protect the public against inf luenza. From a publication in 2018 (Putri et al), the estimated average annual total economic burden of inf luenza on the healthcare system and society was $11.2 billion. Direct medical costs were estimated to be $3.2 billion and indirect costs to be $8.0 billion. These total costs were based on the estimated average numbers of:

i) Ill, non-medically attended patients (21.6 million)

i) Office-based outpatient visits (3.7 million)

iii) Emergency department visits (0.65 million)

iv) Hospitalisations (247.0 thousand)

v) Deaths (36.3 thousand)

vi) Days of productivity lost (20.1 million).

This study suggests that substantial costs from inf luenza remain despite the vaccination efforts in the US. The total direct and indirect costs of inf luenza were equal to $34.8 per capita annually (direct $10.0 and indirect $24.9) with the total costs equal to approximately 0.35% of US per capita health expenditure.

Economic evaluations in health can be a very useful complement to the decision-making process, so methodological approaches should be continually refined and improved. Caution must be exercised in interpreting the results of economic evaluations performed in a given setting and in extrapolating to a different population, location, healthcare system, and resource use. It’s strongly suggested that economic evaluations should be performed on a regular basis to ensure that the results are valid, up-to-date, and consistent with payer’s views and priorities of the societies which are under research. RWE, aside from clinical outcomes, may also include economic outcomes (vaccination cost comparisons) which are helpful for NITAG’s to decide which populations the vaccines are more cost-effective for, and which provide better value for the money paid.

Data collected from RWE and HEOR can be beneficial in country/region-specific scenarios by allowing us to evaluate vaccine effectiveness and estimate influenza-related costs and benefits. With RWE we may be able to identify future vaccine effectiveness that could be later used as an input within cost-effectiveness models. Alternatively, if it’s feasible, you may estimate the mean healthcare costs per vaccinated subject directly through RWE, and compare those costs across the different vaccines within your analysis. The latter approach is stronger due to the assessment’s use of real healthcare expenses from real patients and comparing those depending on which vaccine was received. These comparisons can be done across regions (South vs North), to evaluate if there are any with higher costs than others, or for estimating any cost differences across different healthcare providers (e.g., Medicare vs Medicaid), and analysing which provider has higher influenza mean costs.

Just as COVID-19 mitigation measures helped reduce the spread of the virus and other infectious pathogens like influenza; as many countries continue to decrease such measures, it is expected that COVID-19, influenza, and other respiratory viruses will increase in viral activity simultaneously. We are already observing prepandemic level resurgences of influenza in the Southern Hemisphere, which are anticipated to be mirrored in the Northern Hemisphere this coming influenza season.

Flu vaccination prevents tens of thousands of hospitalisations each year. For example, during 2019-2020, flu vaccination prevented an estimated 105,000 flu-related hospitalisations.

A 2021 study showed that, among adults, influenza vaccination was associated with a 26% lower risk of ICU admission and a 31% lower risk of death from influenza compared to those who were unvaccinated.

A 2018 study showed that, among adults hospitalised with influenza, vaccinated patients were 59% less likely to be admitted to the ICU than those who had not been vaccinated. Among adults in the ICU with influenza, vaccinated patients on average spent 4 fewer days in the hospital than those who were not vaccinated. All these preventions can easily be extrapolated into monetary savings and reflect not only the clinical, but also the economic benefits of influenza vaccines.