Abstract:
nfluenza causes an estimated 3 to 5 million cases of severe illness annually, along with
substantial morbidity and mortality, particularly in low- and middle-income countries (LMICs).
Currently, Sri Lanka has no influenza vaccination policies and does not offer vaccination within the
public healthcare sector. Therefore, we performed a cost-effectiveness analysis of influenza vaccine
implementation for the Sri Lankan population. We designed a static Markov model that followed a
population cohort of Sri Lankans in three age groups, 0–4, 5–64, and 65+ years, through two potential
scenarios: trivalent inactivated vaccination (TIV) and no TIV across twelve-monthly cycles using
a governmental perspective at the national level. We also performed probabilistic and one-way
sensitivity analyses to identify influential variables and account for uncertainty. The vaccination
model arm reduced influenza outcomes by 20,710 cases, 438 hospitalizations, and 20 deaths compared
to no vaccination in one year. Universal vaccination became cost-effective at approximately 98.01% of
Sri Lanka’s 2022 GDP per capita (incremental cost-effectiveness ratio = 874,890.55 Rs/DALY averted;
3624.84 USD/DALY averted). Results were most sensitive to the vaccine coverage in the 5–64-year-old
age group, the cost of the influenza vaccine dose in the 5–64-years-old age group, vaccine effectiveness
in the under-5-years-old age group, and the vaccine coverage in the under-5-years-old age group. No
value for a variable within our estimated ranges resulted in ICERs above Rs. 1,300,000 (USD 5386.15)
per DALY adverted. Providing influenza vaccines was considered highly cost-effective compared to
no vaccines. However, large-scale national studies with improved data are needed to better inform
estimates and determine the impact of vaccination implementation
