Our study found a low influenza vaccination rates in pregnant women in Quito-Ecuador and identified some barriers that could contribute to low vaccination coverage. Those women who were vaccinated knew about the severity of influenza, about the existence of a vaccine, and perceived vaccination against influenza as safe and effective. Our study also suggests that the main barrier for not receiving the vaccine is the lack of recommendation/offer regarding influenza vaccine by health care providers. Among the determinants, recommendation/offer of vaccine increases the likelihood of pregnant women vaccination. Other factors associated with vaccination were knowledge about vaccine safety and more than five antenatal care visits.
The vaccination rate reported in this study (36.6%) is lower than those reported for Ecuador in 2015–2016 (55%) and 2016–2017 (43%) (5) and for those reported by other countries of the region, such as Venezuela (41%) and Bolivia (49%) for 2015. The highest coverages were reported by Chile (72%), Colombia (72%) and Brazil (83%) (15). In Ecuador, the coverage of all vaccines (including the influenza vaccine) indicates a gradual decrease since 2013 to 2016, and an slightly increase from 2017 (5). The Evaluation of National Strategy of Immunizations (5) revealed two elements related to this fact: 1) the Immunization Program underwent a transition, becoming part of the National Immunization Strategy. This fact implied a disaggregation of functions between different actors without an effective articulation of actions; and 2) the lack of budget allocation in a sustainable manner for operational activities of vaccination strategy. Given these facts and the results of our study, there is an urgent need to implement a contingency plan to improve short-term vaccination coverage and reduce the risk of transmission of vaccine-preventable diseases in Ecuador.
Our results are in agreement with previous studies that show that a compelling recommendation from a provider is one of the most important factors in a pregnant woman’s decision to get vaccinated (19, 29, 32–38). Indeed, our study identified that the lack of recommendation was a barrier for vaccination among pregnant women. Knowledge about influenza and vaccination by health workers has an impact on the decisions made regarding the vaccination of their patients and themselves. Studies show that maternal care providers with high levels of knowledge and positive attitudes consistently discuss and recommend influenza vaccine to their patients in greater proportion than other health providers (20, 28, 39, 40). Similarly, health professionals who know the national guidelines on influenza vaccination are more likely to discuss and recommend the vaccine than those who do not know them (41). To our knowledge, there are no studies in Ecuador on the knowledge and attitudes of health workers regarding the influenza vaccine. Other studies demonstrate that health care workers are often reluctant to receive a vaccine (29, 42, 43), have concerns about side effects, demonstrate a lack of faith in its efficacy and have concerns in the severity of the disease (44, 45). Understanding health provider barriers is vitally important because it is not possible to overcome vaccination barriers among pregnant women if health providers themselves are not fully convinced about benefits of maternal immunization. Therefore, working to promote practices related to the recommendation and offer of influenza vaccination among health care providers will be crucial to improving vaccination coverage during pregnancy.
In our study, women who reported perceiving the influenza vaccine as safe and effective had the highest vaccination rates and vaccine safety concern was a reason for not receiving vaccination among 6.2% of non-vaccinated women. Lack of knowledge due to insufficient information about the safety of the influenza vaccine has previously been linked to lower vaccination rates (23, 24, 46). The vaccine is considered safe throughout pregnancy and during lactation, and has been administered to pregnant women for many years without having observed adverse effects (6, 47). Therefore, efforts are needed to educate pregnant women and the population in general regarding the safety and effectiveness of the influenza vaccine to improve vaccination coverage at this risk group.
In our study, having five or more antenatal visits increase the probability of vaccination which is in accordance to other studies (48–50). Antenatal check-ups are essential to promoting the benefits of influenza vaccination and to offering the vaccine to pregnant women (51). To increase vaccination coverage, it would be necessary to offer the influenza vaccine for a longer period rather than just one or two vaccination campaigns. This strategy would benefit women who have few prenatal visits or who are late in attending their first visit. Altogether, different strategies of vaccine delivery to pregnant women need to be evaluated to inform policy decisions in countries where influenza circulation is not confined to a single seasonal peak.
Our study showed different reasons for not to being vaccinated according to educational level of women. The main reasons for not to being vaccinated among illiterate women or with incomplete basic education was not need/want the vaccine and lack of access to vaccination. Studies have shown that people who have a higher education level and/or household income are more likely to receive preventive health services because they may have more knowledge about the importance of health-preventive care and the effectiveness of preventive strategies and more access to health-related services (52, 53).
Some limitations were identified in this study. Firstly, cross-sectional studies do not allow to infer causality because temporal sequence cannot be established. Second, the study sample was not randomly selected but rather a convenience sample, which makes generalization difficult and affects the external validity. Finally, thirty percent of vaccinated women lacked documentation of influenza vaccine status and self-report of vaccination could be affected by social desirability and forgetfulness; however, analysis of a subsample that included only those with written documentation of vaccination showed similar findings.