Table 3 Excluded studies with reasons

1

Li Chen (2016)

The intervention was EPI application and text reminder sent for both groups

2

Wakadha et al. (2013)

It was a feasibility study with no comparison group of standard care

3

Uddin et al. (2016)

It was quasi-experimental study where the outcome was measured pre and post intervention in both groups

4

Schlumberger et al. (2015)

The abstract was in English but full document was in French. Though the author was contacted but unable to get the English version of the full text

5

Abramson et al. (1995)

Interventions were reminder cards and phone calls

6

Morgan et al. (1998)

Interventions were telephone call and mailed reminders

7

Aragones et al. (2015)

Population includes children above 5 years of age

8

Bjornson et al. (1999)

Interventions were mailed reminders

9

Kempe et al. (2015)

It was a pragmatic trial with interventions mail and autodialed telephone calls

10

Stockwell et al. (2015)

Population extends above 5 years (6 months up to 8 years) with no disaggregation for under-five children

11

Zhou-Chen et al. (2008)

Outcome was improving attendance rates at a health promotion center

12

Macknin et al. (2000)

Population extends beyond under 5 years (0–18 years) and no separate data for children

13

Sther–Geen et al. (1993)

Interventions were voice calls

14

Hofstetter et al. (2015)

Population beyond under 5 years (6 months to 17 years) with educational and interactive messages

15

Lieu et al. (1998)

The study did not randomize patients to no intervention group

16

Dombkowski et al. (2014)

Intervention was mailed recall and reminder

17

O’Leary et al. (2015)

Population was adolescents without under-five children

18

Irigoyen et al. (2000)

Interventions were phone calls and post card reminders