Fifty-four articles in total: 24 influenza, 11 pneumonia, 1 hepatitis B, 13 MMR and 5 DPTP.
ADULT IMMUNISATIONS
1. Influenza.
Type of intervention:
Client-orientated: pooled effect 12.2% (95% CI: 10.6, 13.7). Provider-orientated: pooled effect 18.1% (95% CI: 16.5, 19.8). System-orientated: pooled effect 39.4% (95% CI: 29.7, 49.0). Mixed: pooled effect 16.8% (95% CI: 14.8, 18.8). Total: pooled effect 18.6% (95% CI: 17.7, 19.5).
Target population coverage:
Hospitalised populations: pooled effect 61.7% (95% CI: 45.2, 78.2). Out-patient populations: pooled effect 15.9% (95% CI: 15.0, 16.9).
Study design effect on coverage:
RCTs: pooled effect 12.9% (95% CI: 10.2, 15.7). Other designs: pooled effect 27.1% (95% CI: 25.5, 28.7).
Effect of internal study validity on coverage:
Strong or moderate: pooled effect 17.9% (95% CI: 17.9, 21.1). Weak: pooled effect 20.0% (95% CI: 18.4, 21.6).
Baseline population coverage:
Baseline less than 20%: pooled effect 20.5% (95% CI: 17.9, 21.1). Baseline 20 to 50%: pooled effect 19.3% (95% CI: 17.5, 21.2). Baseline greater than 50%: pooled effect 14.8% (95% CI: 12.3, 17.3).
2. Pneumococcal.
Type of intervention:
Client-orientated: pooled effect 75.0% (95% CI: 64.4, 85.6). Provider-orientated: pooled effect 7.5% (95% CI: 3.4,11.6). System-orientated: pooled effect 45.5% (95% CI: 37.2, 53.7). Mixed: pooled effect 5.5% (95% CI: -1.9, 12.9). Total: pooled effect 29.7% (95% CI: 24.9, 34.5).
Target population coverage:
Hospitalised populations: pooled effect 53.4% (95% CI: 34.8, 72.1). Out-patient populations: pooled effect 2.7% (95% CI: -2.2, 7.6). General population: pooled effect 18.7% (95% CI: -1.6, 39.9).
Study design effect on coverage:
Clinical trials: pooled effect 28.7% (95% CI: 24.1, 33.3). RCTs: pooled effect 8.6% (95% CI: 4.5,12.6). Trials: pooled effect 7.5% (95% CI: 70.0, 83.4). Observational study: pooled effect 28.9% (95% CI: 20.6, 37.1). Cohort: pooled effect 45.5% (95% CI: 10.0, 90.7). Community study:pooled effect 5.5% (95% CI: -1.6, 3.9).
Effect of internal study validity on coverage:
Strong: pooled effect 34.6% (95% CI: -0.6, 69.8). Moderate: pooled effect 78.0% (95% CI: 72.3, 83.8). Weak: pooled effect 18.5% (95% CI: 17.7, 19.3).
Baseline population coverage:
Insufficient data: in only 3 comparisons was the baseline rate above 20% (excluding non-independent intervention effects).
3. Hepatitis B
Only one study was included. This was an RCT judged to be of weak internal validity.
Increased coverage of target population:
Mailing only: 1.9% (95% CI: -4.1, 7.9). Mailing plus decision analysis: 6.3% (95% CI: 1.0, 11.6).
CHILDHOOD IMMUNISATIONS
4. MMR.
Type of intervention:
Pooling of studies was not deemed appropriate because of differences in, e.g. intervention and target population.
Client-orientated: of the 2 included studies, 1 increased coverage by 62% (baseline 3.1%) and the other increased coverage by 5% (baseline 42%).
System-orientated: studies were concerned with legislation, public versus private type of services and technical resources. Legislation was found to have the biggest effect.
Target population coverage:
In children of school age or older, all studies showed effects of 44% or higher. In pre-school children the effect of interventions ranged from -43.5 to 25%.
Effect of internal study validity on coverage:
Only 3 of 8 studies were rated as strong or moderate. A letter reminder had little effect (5%); legislation had a large effect (44%); and a change in the immunisation schedule resulted in a decrease in coverage (-42%).
Baseline population coverage:
Most studies had a baseline coverage rate between 30 and 70%, with the exception of one study that had a baseline coverage rate of 3.1%.
5. DPTP.
The calculation of pooled effects was inappropriate because of the small number of studies.
Only individual effects of the interventions evaluated in each study are presented. Feedback of immunisation practice resulted in large effects (56.1%, 95% CI: 42.2, 70.0) as did postcard reminders (33.9%, 95% CI: 19.9, 48.0). Changing the timing of MMR vaccination from 12 to 15 months resulted in a decrease in coverage levels of the DPT booster at 18 months.