Are We Prepared for the Upcoming Seasonal Influenza Epidemic?

Dear Editor, Between 2010 and 2017, 114,667 cases and 8543 deaths were attributed to influenza in India, with a case fatality rate of 7.5%. The reported hospitalization rate secondary to influenza is 46.8/10,000 patients.1 This burden of influenza on Indian healthcare resources justifies the recommendation by the Indian Guidelines for yearly influenza vaccination with quadrivalent inactivated influenza vaccine in adults above 50 years of age, and in vulnerable population groups irrespective of age.2 The reported efficacy of the vaccine of 54% and 42% during the influenza seasons 2022–2023 and 2023–2024, respectively, in the United States, is unimpressive.3 However, a narrative review published in 2021, identified a 26% reduction in intensive care unit (ICU) admission and 31% reduced risk of death in vaccinated adults when compared to unvaccinated adults.4 This should give impetus to push forward with influenza vaccination to the target population. But is the eligible population group receiving the recommended vaccination? To answer this question, we proceeded to conduct a retrospective review of our hospital records and share our results. 671 of 2552 samples tested at our institute in 2023 returned positive for influenza infection by polymerase chain reaction (PCR). A retrospective analysis of a cohort of 50 hospitalized patients with PCR-confirmed influenza A (including H1N1) and B infection admitted under pulmonary medicine during the last seasonal influenza epidemic period between September and December 2023 was performed Table 1. Out of them, 40 patients consented to participate in the study. 7 out of 40 patients (17.5%) were aware of the existence of the influenza vaccine. Three of 40 patients (7.5%) patients were vaccinated for influenza. 33 of 37 (89.2%) patients who were unvaccinated cited a lack of awareness of the vaccine for nonvaccination Table 2. The average length of hospital stay was 6.5 days. An additional average expense of 27500 INR was incurred per patient when comparing hospitalization vis-à-vis vaccination. The expenses were higher for patients who required ICU care. 26 patients (65%) with preexisting lung disease, and on regular follow-up with their doctors either in our institute or elsewhere, remained unaware about the influenza vaccine. Overall, 36 of 40 patients (90%) were eligible for vaccination. Data from our pharmacy suggest a total of 602 influenza vaccines were dispensed in 2023, which is disheartening, considering that we see over 2000 patients in respiratory outpatient department (OPD) per month, with the majority having chronic respiratory diseases.Table 1: Baseline characteristics, in hospital clinical course and clinical outcomes of study group (n=40)Table 2: Vaccination status of patients in study group (n=40)Our research has drawbacks: selection bias and small study group. However, it shows that the patients who would benefit from the vaccine the most, failed to receive it. Physicians attending the OPD failed to recognize opportunities to counsel and administer vaccines, either due to a busy OPD, or overlooked the vaccination status of the patients. Majority of these patients regularly visit their primary care physician, offering an opportunity for personal counseling to improve vaccination uptake. We propose that measures such as an outpatient checklist for adult vaccinations be provided to all patients, and posters that project the availability and effectiveness of vaccination be displayed at OP clinics.5 With the upcoming seasonal influenza epidemic looming in the south, we have to take extra effort to ensure that patients who are likely to benefit from vaccination, get their due vaccines at the earliest. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.