Influenza Vaccination Coverage among Multiple Sclerosis Patients: Evolution over Time and Associated Factors

Abstract

Our objective was to determine the influenza vaccination rate in a Spanish cohort of multiple sclerosis (MS) patients. A retrospective cohort study was carried out. Patients who attended the MS unit of the Lozano Blesa Hospital of Zaragoza between January 2015 and 2020 were included. The variables were obtained by reviewing the specialized and primary care records. Associations between receiving the vaccine in each flu season and the other variables were analyzed using bivariate analysis and multiple logistic regression models. A total of 260 patients were studied, with a median age of 31 years at the time of diagnosis. A total of 62.3% (162/260) were women. Vaccination coverage ranged from 20.4% in the 2015–2016 and 2016–2017 seasons to 41.5% in the 2019–2020 season (p = 0.000). Having been vaccinated in the previous season (ORa: 16.47–390.22; p = 0.000) and receiving a vaccination recommendation from the hospital vaccination unit (ORa: 2.44–3.96; p < 0.009) were associated with being vaccinated. The coverage is in an intermediate position compared to other countries. It is necessary to improve the referral system of these patients to the hospital vaccination unit because the information obtained by this service contributed to higher vaccination rates.

Influenza Vaccination among Multiple Sclerosis Patients during the COVID-19 Pandemic

“…In contrast to other studies conducted prior to the coronavirus pandemic (COVID-19) caused by SARS-CoV-2 [ 14 , 15 ], having received the recommendation by healthcare personnel to be vaccinated was not associated with receiving the flu vaccine in 2020–2021. This may indicate that the context of the COVID-19 pandemic has contributed to patients who have not received this advice and who have not been vaccinated to date deciding to get vaccinated in the 2020–2021 season.…”

“…Likewise, the rate obtained (55.3%) is higher than that described to date in Spain in patients with MS (from 20.4% in the 2016–2017 season to 41.5% in the 2019–2020 season) [ 14 ]. However, such rate is lower than that achieved in Spain during the 2020–2021 campaign in other groups targeted for vaccination, such as healthcare personnel (62.0%), those over 65 years of age (67.7%) and pregnant women (61.9%) [ 25 ].…”

“…Among the limitations of this study is the sample size (302), which, although larger than the sample sizes in other studies [ 15 , 17 , 23 , 24 ] (from 101 [ 23 ] to 194 [ 17 ]), may have led to imprecise results. Nevertheless, the sample size is greater than 291, which is the minimum number to be studied considering a confidence level of 95%, a precision of 5%, a population of 1300 people [ 20 ] and an expected vaccination rate of 41.5% [ 14 ]. Although our research was conducted in an MS unit, it provides an example of a systematic approach to the evaluation of flu vaccination coverage in MS patients that could be carried out in other MS units [ 14 ].…”

“…Nevertheless, the sample size is greater than 291, which is the minimum number to be studied considering a confidence level of 95%, a precision of 5%, a population of 1300 people [ 20 ] and an expected vaccination rate of 41.5% [ 14 ]. Although our research was conducted in an MS unit, it provides an example of a systematic approach to the evaluation of flu vaccination coverage in MS patients that could be carried out in other MS units [ 14 ]. Despite the fact that this was a registry study, there were no missing data about vaccinations because such information is always recorded in the electronic medical record (in its vaccines section).…”

“…For this reason, public health institutions [ 6 , 7 ], scientific societies [ 8 , 9 , 10 ] and expert groups [ 5 , 11 ] recommend annual influenza vaccination for patients with MS. However, the vaccination coverage in this population is low [ 12 , 13 , 14 , 15 , 16 , 17 ], with the rates in Europe ranging from 19% in Germany [ 12 ] to 63.8% in Ireland [ 15 ] ( Table 1 ), while in the Americas, they range from 45.4% in Latin America [ 16 ] to 59.1% in the USA [ 13 ].…”