This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Contacting patients by telephone or mail about recommended immunisations leads to eight more people in every 100 being immunised. Text messages, postcards or automatic dialling techniques and recorded voices are the reminder methods that have the highest certainty of being effective.
In the UK over 90% of children currently receive the recommended immunisation programme, but this is still below optimal to prevent infection. The uptake of the influenza vaccination in over 65s is also below national coverage goals.
This updated Cochrane review identified 75 studies measuring the effect of contacting patients when immunisations are due or overdue. There was evidence for improved uptake of child and adolescent vaccinations, and for adults having the influenza vaccine.
The international studies covered a variety of settings across different countries with relatively low baseline vaccination rates. The evidence reinforces the benefit of recalls and reminders.
Even small increases in vaccination uptake could make a difference in population coverage and so could have a meaningful public health impact.
Why was this study needed?
Immunisations are important to protect individuals and communities from serious infections. People who cannot have immunisations for health reasons are protected because of the high level of immunity in the population which stops unimmunised people from coming into contact with infections. This is known as herd immunity. If the level of immunisation drops, then diseases can spread among unimmunised individuals.
In 2016-17, 93.4% of children completed the three-course immunisation for diphtheria, tetanus, pertussis, polio and haemophilus influenzae type B before their first birthday. 91.6% received the measles, mumps and rubella vaccination before their second birthday. However, these rates present a small decline on previous years.
Uptake of the influenza vaccination among over 65s is much lower at 70.5% from September 2016 to January 2017.
This update of a Cochrane review last published in 2008 adds 28 new studies assessing how contacting patients about due (reminders) or overdue immunisations (recalls) affects uptake.
What did this study do?
This update identified a total of 75 studies, which were mostly randomised controlled trials, although five used a before-and-after design. Meta-analysis was performed for 55 studies with 138,625 participants.
Fifty-eight studies came from the USA with others from a selection of mostly high-income countries. Two came from the UK. Settings were highly varied including schools, private practices and public health departments. Twenty-nine studies examined routine childhood vaccinations, 24 adult flu vaccines and five child flu vaccines.
Thirty-two studies assessed reminder or recall letters, 10 used postcards, 14 telephone calls, six text messages and seven interventions using automatic dialling techniques with recorded messages. The remainder used a combination of interventions. Interventions varied from one-off reminders/recalls to intermittent contact over one year. Highest possibility of bias seemed to be awareness of group allocation, either at randomisation or when outcomes were assessed.
What did it find?
- Contacting patients about due or overdue immunisations increased uptake by eight percentage points. Thirty-seven per 100 people receiving recalls or reminders were immunised compared with 29 per 100 who were not contacted (relative risk [RR] 1.28, 95% confidence interval [CI] 1.23 to 1.35). This was based on 55 studies with 138,625 participants with moderate certainty of the evidence.
- Similar effects were seen in subgroup analyses for contacting patients about childhood immunisations (41% immunised vs. 33%; RR 1.22, 95% CI 1.15 to 1.29; 23 studies, 31,099 participants) and adolescent immunisations (31% vs 24%; RR 1.29, 95% CI 1.17 to 1.42, 10 studies, 30,868 participants), both with high certainty of the evidence.
- There was moderate certainty that contacting patients about adult influenza vaccination was effective (38% vs 29%; RR 1.29, 95% CI 1.17 to 1.43; 15 studies, 59,328 participants). There was an even larger effect for childhood influenza vaccination, though this was based on fewer studies (65% vs 43%; RR 1.51, 95% CI 1.14 to 1.99; 5 studies, 9,265 participants).
- By specific method, there was highest certainty of evidence for the effectiveness of post cards (RR 1.18, 95% CI 1.08 to 1.30; eight studies, 27,734 participants), text messages (RR 1.29, 95% CI 1.15 to 1.44, six studies, 7,772 participants) and autodialer messages (RR 1.17, 95% CI 1.03 to 1.32; five studies, 11,947 participants). Telephone calls and letters are also likely to be effective based on moderate certainty evidence.
What does current guidance say on this issue?
NICE’s public health guideline on reducing the difference in uptake of immunisations in under 19s notes: “Send tailored invitations for immunisation. When a child or young person does not attend appointments, send tailored reminders and recall invitations and follow them up by telephone or text message.”
The Public Health England green book Immunisation against infectious disease does not mention reminder or recall interventions.
What are the implications?
The large body of evidence supports recommendations around recalls and reminders for child immunisations. It suggests the strategy may also benefit other age groups, such as adult influenza vaccination.
The baseline immunisation rate across these pooled international studies was fairly low at around a third, much lower than UK coverage, even with declining rates. Increased uptake by about eight percentage points could make a big difference here, but it's uncertain if this would apply to the UK.
It may be helpful to consider how reminder and recall methods can be tailored to meet the needs of specific patient groups.
Citation and Funding
Jacobson Vann JC, Jacobson RM, Coyne-Beasley T, et al. Patient reminder and recall interventions to improve immunization rates. Cochrane Database Syst Rev. 2018;CD003941.
This project was funded by the NIHR, via Cochrane Infrastructure funding to the Effective Practice and Organisation of Care Group.
Caan W. Telephone first consultations may discriminate against people with disabilities. BMJ. 2017;359:j4905.
NICE. Flu vaccination: increasing uptake. GID-PHG96. London: National Institute for Health and Care Excellence; in development.
NICE. Immunisations: reducing differences in uptake in under 19s. PH21. London: National Institute for Health and Care Excellence; 2009.Public Health England. Immunisation against infectious disease: the green book. London: Public Health England; 2013.
Public Health England. Seasonal influenza vaccine uptake in GP patients in England: winter season 2016 to 2017. London: Public Health England; 2017.
Khan R. Polio vaccination team ambushed and two members killed in remote tribal region of Pakistan. London: The Independent; 19 March 2018.
Screening & Immunisations Team, NHS Digital. Child vaccination coverage statistics, England, 2016-17. Richmond: Health and Social Care Information Centre; 2017.
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