Timeliness of immunisation with the pentavalent vaccine at different levels of the health care system in the Lao People’s Democratic Republic: A cross-sectional study

Abstract

Background The timely administration of vaccines is considered to be important for both individual and herd immunity. In this study, we investigated the timeliness of the diphtheria-tetanus-whole cell pertussis-hepatitis B-Haemophilus influenzae type b (pentavalent) vaccine, scheduled at 6, 10 and 14 weeks of age in the Lao People’s Democratic Republic. We also investigated factors associated with delayed immunization. Methods 1162 children aged 8–28 months who had received the full course of the pentavalent vaccine at different levels of the health care system were enrolled. Vaccination dates documented in hospital records and/or immunisation cards were recorded. Age at vaccination and time intervals between doses were calculated. Predictors for timely completion with the pentavalent vaccine at 24 weeks were assessed by bivariate and multivariable analyses. Results Several discrepancies in dates between vaccination documents were observed. In general, vaccination with the pentavalent vaccine was found to be delayed, especially in health care settings below the provincial hospital level. Compared to the central hospital level, less participants who were vaccinated at the district/health center level received the third dose by 16 (48% at the central hospital level vs. 7.1% at the district and 12.4% at the health center level) and 24 weeks of age (94.4% at the central hospital level vs 64.6% at the district-outreach and 57.4% at the health center level) respectively. In logistic regression analyses, lower education level of the mother as well as vaccination by outreach service, were independently associated with delayed completion of vaccination. Conclusion We observed a general delay of vaccination, especially at lower ranked facilities, which correlated with indicators of poor access to health services. This highlights the need for further improving health equity in rural areas. Age-appropriate vaccination should become a quality indicator for the national immunization programme. In addition, we recommend further training of the health care staff regarding the importance of reliable documentation of dates.

Seroprevalence of measles and rubella antibodies in vaccinated and unvaccinated infants in the Lao People’s Democratic Republic

“…In 2019, the nationwide vaccination coverage with MR was estimated to be 69% (World Health Organization and United Nations Children's Fund, 2019b). Since problems with health records and management in Lao PDR have been observed previously by us (Hefele et al, 2020) and others (Sychareun et al, 2014), we cannot exclude the possibility that some of the documented vaccinated children had not received their vaccination or vice versa.…”

“…However, the proportion of participants vaccinated after 12 months of age increased from 6% at the central hospitals to 33.7-46.7% in lower ranked HCFs. We have previously observed vaccination delays in lower levels of the health care system for the pentavalent vaccine (Hefele et al, 2020). Vaccination coverage and vaccination timeliness are separate issues but they are connected: delays in routine vaccination increase the risk of missed opportunities.…”

“…The specific place of vaccination (by outreach service or on site) was based on parental recall since it is not recorded in the vaccination documents. We have observed mismatches of vaccination dates on the vaccination cards and in the hospital records before (Hefele et al, 2020) and cannot exclude that not all participants with a vaccination date were truly vaccinated.…”