Influenza Vaccination in Asplenia: Improving Quality of Care in Time of Coronavirus

Introduction

Asplenic patients are at high risk of potentially fatal invasive infections, such as sepsis, meningitis, and pneumonia. It has been shown that infection from influenza viruses can precede or increase the risk of bacterial infection and of serious complications of the underlying disease. International and national guidelines recommend annual influenza vaccination in asplenic subjects. Following the Covid-19 pandemic, the major government and medical-scientific institutions in the US and in Europe have been planning how to contain infection during the 2020-2021 influenza season. Extending influenza vaccination is the safest and most effective way to reduce the circulation of influenza virus and to promote the correct diagnosis and management of suspected cases of SARS-CoV-2. Influenza vaccination also reduces complications associated with the underlying disease and visits to Emergency Units. Our study aims to evaluate influenza vaccination in a large population of asplenic patients and explore the main causes for non-vaccination to identify critical areas for improvement in the vaccination programme in these at-risk patients for the 2020-2021 influenza season.

Methods

The Italian Network of Asplenia (INA) is made up of 88 doctors working in 50 clinical centers in 27 cities and 16 of the 20 regions of Italy. It aims to build a large, prospective cohort of asplenic patients throughout Italy through which to study the interaction between asplenia and its associated underlying conditions, collecting precise, accurate data also in cases of rarer diseases. The study also aims to improve the quality of healthcare for this at-risk population. The number of patients enrolled in the Network who had had at least one dose of influenza vaccine at the time of diagnosis of asplenia was retrieved from the INA database. All participating centers were asked to answer a questionnaire to report the main obstacles for influenza vaccination.

Results

At 1st August 2020, 1,670 patients had been enrolled in the INA (783 females; 887 males). All underlying causes of asplenia are shown in Table 1. Only 466 (28%) patients had had at least one influenza vaccination, while 1,204 (72%) had never been vaccinated since diagnosis of asplenia. Thirty-five (70%) of the 50 centers answered the questionnaire. Main causes of non-vaccination were physicians' ambivalence concerning vaccination and patients' inadequate awareness or logistical problems.

Conclusions

These data show very low seasonal influenza vaccination cover even though asplenic patients are considered at-risk of complications associated with infection from influenza viruses. Since the 2020-2021 influenza season could see influenza viruses in circulation with SARS-CoV-2, influenza vaccination must be expanded as widely as possible, in particular to subjects of all ages at high risk. These results reveal important areas of concern in the management of asplenic patients and the need to improve the quality of information to physicians and patients alike. The INA co-ordinating center will launch a campaign to provide information and organize ad hoc meetings to widen influenza vaccination coverage in asplenic patients and reduce the pressure on the national health service during the next influenza season.