Assessment of the benefits of seasonal influenza vaccination: Elements of a framework to interpret estimates of vaccine effectiveness and support robust decision‐making and communication

BACKGROUND Seasonal influenza vaccination (SIV) coverage among young children remains low worldwide. Mobile social-networking applications such as WhatsApp Messenger are promising tools for health interventions. OBJECTIVE This was a preliminary study to test the effectiveness and parental acceptability of social-networking intervention that sends weekly vaccination reminders and encourages exchange of SIV-related views and experience among mothers via WhatsApp discussion groups for promoting childhood SIV. The second objective was to examine the effect on mothers’ decision-making for childhood SIV of additionally introducing time pressure for vaccination decision-making using countdowns of the recommended vaccination timing. METHODS Mothers of child(ren) aged 6-72 months were randomly allocated to Control, or one of two social-networking Intervention groups receiving vaccination reminders with (SNI/+TP) or without (SNI/-TP) a time pressure component via WhatsApp discussion groups at a ratio of 5:2:2. All participants first completed a baseline assessment. Both the SNI/-TP and SNI+TP groups subsequently received respective weekly vaccination reminders in Oct-Dec 2017, and participated in WhatsApp discussions about SIV moderated by a health professional. All participants completed a follow-up assessment in April-May 2018. RESULTS A total of 174 (84.9%, 174/205), 57 (71.3%, 57/80) and 60 (75.0%, 60/80) who were allocated into the Control, SNI/-TP and SNI/+TP, respectively, completed the outcome assessment. The social-networking intervention significantly promoted mothers’ self-efficacy for taking children for SIV (SNI/-TP: OR=2.69 (1.07-6.79); SNI/+TP: OR=2.50 (1.13-5.55)), but did not result in significantly improved children’s SIV uptake. Moreover, after adjusting for mothers’ working status, introducing additional time pressure reduced the overall SIV uptake in children of working mothers (OR=0.27 (0.10-0.77)) but significantly increased the SIV uptake among children of mothers without a full-time job (OR=6.53 (1.87-22.82)). Most participants’ WhatsApp posts were about sharing experience/views (52.1%, 226/434) of which 44.7% (101/226) were categorized as negative such as their concerns over vaccine safety/side effects and effectiveness. Though participants shared predominantly negative experience/views about SIV at the beginning of the discussion, the moderator was able to encourage the discussion of more positive experience/views and more knowledge/information. Most Intervention group participants indicated willingness to receive the same interventions (94.0%, 110/117) and recommend the interventions to other mothers (87.2%, 102/117) in future. CONCLUSIONS Online information support can effectively promote mothers’ self-efficacy for taking children for SIV but may not alone be sufficient to address maternal concerns over SIV to achieve a positive vaccination decision. However, the active involvement of health professionals in online discussions can shape positive discussions about vaccination. Time pressure on decision-making interacts with maternal work status, facilitating vaccination uptake among mothers who may have more free time job but having the opposite effect among busier working mothers. CLINICALTRIAL HKUCTR-2250, www.HKUCTR.com

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Cohort study design for estimating the effectiveness of seasonal influenza vaccines in real time based on register data: The Finnish example

Scandinavian Journal of Public Health ◽

10.1177/1403494818808635 ◽

2018 ◽

Vol 48 (3) ◽

pp. 316-322

Author(s):

Ulrike Baum ◽

Kari Auranen ◽

Sangita Kulathinal ◽

Ritva Syrjänen ◽

Hanna Nohynek ◽

...

Keyword(s):

At Risk ◽

Cohort Studies ◽

Influenza Vaccination ◽

Real Time ◽

Seasonal Influenza ◽

Time Estimation ◽

Vaccine Effectiveness ◽

Loss To Follow Up ◽

Seasonal Influenza Vaccination ◽

Cohort Study Design

This paper presents the principles of implementing register-based cohort studies as currently applied for real-time estimation of influenza vaccine effectiveness in Finland. All required information is retrieved from computerised national registers and deterministically linked via the unique personal identity code assigned to each Finnish resident. The study cohorts comprise large subpopulations eligible for a free seasonal influenza vaccination as part of the National Vaccination Programme. The primary outcome is laboratory-confirmed influenza. Each study subject is taken to be at risk of experiencing the outcome from the onset of the influenza season until the first of the following three events occurs: outcome, loss to follow up or end of season. Seasonal influenza vaccination is viewed as time-dependent exposure. Accordingly, each subject may contribute unvaccinated and vaccinated person-time during their time at risk. The vaccine effectiveness is estimated as one minus the influenza incidence rate ratio comparing the vaccinated with the unvaccinated within the study cohorts. Data collection in register-based research is an almost fully automated process. The effort, resources and the time spent in the field are relatively small compared to other observational study designs. This advantage is pivotal when vaccine effectiveness estimates are needed in real time. The paper outlines possible limitations of register-based cohort studies. It also addresses the need to explore how national and subnational registers available in the Nordic countries and elsewhere can be utilised in vaccine effectiveness research to guide decision making and to improve individual health as well as public health.

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Influenza-Associated Medical Visits Prevented by Influenza Vaccination in Young Children in Thailand, 2012–2014

Journal of the Pediatric Infectious Diseases Society ◽

10.1093/jpids/piaa076 ◽

2020 ◽

Author(s):

Melissa A Rolfes ◽

Sonja J Olsen ◽

Wanitchaya Kittikraisak ◽

Piyarat Suntarattiwong ◽

Chonticha Klungthong ◽

...

Keyword(s):

Young Children ◽

Influenza Vaccination ◽

Seasonal Influenza ◽

Vaccine Effectiveness ◽

Seasonal Influenza Vaccination ◽

Medical Visits ◽

Effectiveness Data

Abstract Despite recommendations, few children aged 6–35 months in Thailand receive seasonal influenza vaccination. Using previously estimated incidence and vaccine effectiveness data from the period 2012–2014, we estimate that up to 121 000 medical visits could be prevented each year with 50% coverage and expanded recommendations to children aged <5 years.

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