Kimona Rampersadh

Background: Immunization is a highly effective intervention for controlling over 20 life-threatening infectious diseases, significantly reducing both morbidity and mortality rates. One notable achievement in vaccination efforts was the global eradication of smallpox, which the World Health Assembly declared on 8 May 1980. Additionally, there has been a remarkable 99.9% reduction in wild poliovirus cases since 1988, decreasing from more than 350,000 cases that year to just 30 cases in 2022. Objectives: The objective of this review was to assess the effects of various interventions designed to increase vaccination uptake among adults. Search Methods: A thorough search was conducted in the CENTRAL, Embase Ovid, Medline Ovid, PubMed, Web of Science, and Global Index Medicus databases for primary studies. This search was conducted in August 2021 and updated in November 2024. Selection Criteria: Randomized trials were eligible for inclusion in this review, regardless of publication status or language. Data Analysis: Two authors independently screened the search outputs to select potentially eligible studies. Risk ratios (RR) with 95% confidence intervals (CI) were calculated for each randomized controlled trial (RCT). A meta-analysis was conducted using a random-effects model, and the quality of the evidence was assessed using the GRADE approach. Main Results: A total of 35 randomized controlled trials met the inclusion criteria and were included in this review, with the majority conducted in the United States. The interventions targeted adults aged 18 and older who were eligible for vaccination, involving a total of 403,709 participants. The overall pooled results for interventions aimed at increasing influenza vaccination showed a risk ratio of 1.41 (95% CI: 1.15, 1.73). Most studies focused on influenza vaccination (18 studies), while the remaining studies examined various other vaccines, including those for hepatitis A, COVID-19, hepatitis B, pneumococcal disease, tetanus, diphtheria, pertussis (Tdap), herpes zoster, and human papillomavirus (HPV). The results indicate that letter reminders were slightly effective in increasing influenza vaccination uptake compared to the control group (RR: 1.75, 95% CI: 0.97, 1.16; 6 studies; 161,495 participants; low-certainty evidence). Additionally, participants who received education interventions showed increased levels of influenza vaccination uptake compared to those in the control group (RR: 1.88, 95% CI: 0.61, 5.76; 3 studies; 1318 participants; low-certainty evidence). Furthermore, tracking and outreach interventions also led to an increase in influenza vaccination uptake (RR: 1.87, 95% CI: 0.78, 4.46; 2 studies; 33,752 participants; low-certainty evidence). Conclusions: Letter reminders and educational interventions targeted at recipients are effective in increasing vaccination uptake compared to control groups.

Background Immunisation is an effective intervention for controlling more than 20 life-threatening infectious diseases, reducing both morbidity and mortality. One major vaccination-related achievement was the worldwide eradication of smallpox; the world was declared free of smallpox by the World Health Assembly on 8 May 1980. A second major vaccination-related success has been a reduction in wild poliovirus cases by 99.9% since 1988, from more than 350,000 incident cases that year to 30 in 2022. Objectives To assess the effects of interventions aimed at increasing vaccination uptake among adults. Search methods A search was conducted in CENTRAL, Embase Ovid, Medline Ovid, PubMed, Web of Science, and Global Index Medicus databases for primary studies, in August 2021, and updated in November 2024. Selection criteria Randomised trials, irrespective of their publication status and language of publication, were eligible for inclusion in this review. Data collection and analysis Two review authors independently screened records, assessed full-text articles to identify potentially eligible studies, extracted data, and evaluated risk of bias, resolving differences by consensus. For each included study, we calculated risk ratios (RR) with 95% confidence intervals (CI). We pooled study results using random-effects meta-analyses and used GRADE to assess the certainty of the evidence. Main results Thirty-five randomised controlled trials met the inclusion criteria and were included in the review, the majority of which were conducted in the United States of America (U.S.A.). The interventions were aimed at improving vaccination uptake among adults aged 18 years and above who were eligible for vaccination. Most of the studies assessed uptake of influenza vaccine (18 studies), with the rest investigating a variety of vaccines, including hepatitis A virus, coronavirus disease of 2019 (COVID-19), hepatitis B virus, pneumococcal, tetanus, diphtheria, and pertussis (Tdap), herpes zoster (the acronym would be either: herpes zoster vaccine (HZV) or recombinant zoster vaccine (RZV) or live shingles zoster vaccine (ZVL) ), and human papillomavirus (HPV) vaccines (18 studies). Our results indicate that letter reminders were slightly effective in increasing influenza vaccination uptake compared to the control (RR: 1.75, 95% CI: 0.97, 1.16; 6 studies; 161,495 participants; low-certainty evidence). There were increased levels of influenza vaccination uptake among participants who received education interventions compared to those who were in the control group (RR: 1.88, 95% CI: 0.61, 5.76; 3 studies, 1,318 participants; low-certainty evidence). Tracking and outreach interventions also increased the influenza vaccination uptake (RR:1.87, 95% CI: 0.78, 4.46; 2 studies, 33,752 participants; low-certainty evidence). Conclusion Letter reminders and education directed at recipients are effective in increasing vaccination uptake compared to the controls.