Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Aug 5;34(36):4321-6.
doi: 10.1016/j.vaccine.2016.06.074. Epub 2016 Jul 12.

Diphtheria outbreak in Lao People's Democratic Republic, 2012-2013

Carolyn Sein  1 , Tejpratap Tiwari  2 , Adam Macneil  3 , Kathleen Wannemuehler  3 , Chanthavy Soulaphy  4 , Phouthone Souliphone  4 , Rita Reyburn  5 , Alejandro Ramirez Gonzalez  5 , Margaret Watkins  3 , James L Goodson  3
Affiliations

Diphtheria outbreak in Lao People's Democratic Republic, 2012-2013

Carolyn Sein et al. Vaccine. .

Abstract

Background: Diphtheria is a vaccine-preventable disease. When vaccination coverage and population immunity are low, outbreaks can occur. We investigated a diphtheria outbreak in Lao People's Democratic Republic that occurred during 2012-2013 and highlighted challenges in immunization services delivery to children in the country.

Methods: We reviewed diphtheria surveillance data from April 1, 2012-May 31, 2013. A diphtheria case was defined as a respiratory illness consisting of pharyngitis, tonsillitis, or laryngitis, and an adherent tonsillar or nasopharyngeal pseudomembrane. To identify potential risk factors for diphtheria, we conducted a retrospective case-control study with two aged-matched neighborhood controls per case-patient in Houaphan Province, using bivariate analysis to calculate matched odds ratio (mOR) with 95% confidence intervals (CI). Reasons for non-vaccination among unvaccinated persons were assessed.

Results: Sixty-two clinical cases of diphtheria and 12 diphtheria-related deaths were reported in seven of 17 provinces. Among case-patients, 43 (69%) were <15years old, five (8%) reported receiving three DTP doses (DTP3), 21 (34%) had received no DTP doses, and 35 (56%) had unknown vaccination status. For the case-control study, 42 of 52 diphtheria case-patients from Houaphan province and 79 matched-controls were enrolled. Five (12%) case-patients and 20 (25%) controls had received DTP3 (mOR=0.4, CI=0.1-1.7). No diphtheria toxoid-containing vaccine was received by 20 (48%) case-patients and 38 (46%) controls. Among case-patients and controls with no DTP dose, 43% of case-patients and 40% of controls lacked access to routine immunization services.

Conclusion: Suboptimal DTP3 coverage likely caused the outbreak. To prevent continued outbreaks, access to routine immunization services should be strengthened, outreach visits need to be increased, and missed opportunities need to be minimized. In the short term, to rapidly increase population immunity, three rounds of DTP immunization campaign should be completed, targeting children aged 0-14years in affected provinces.

Keywords: Diphtheria; Lao PDR; Outbreak; Vaccination; Vaccine-preventable.

PubMed Disclaimer

Conflict of interest statement

Conflict of interest

The authors declare that they have no conflict of interest.

Figures

Fig. 1.
Fig. 1.
(a and b) Physical signs of diphtheria infection: pseudomembrane in 1a (Houaphan Province), and bull neck in 1b (Vientiane Capital)* – Lao People’s Democratic Republic, 2012–2013. *Photos sourced from and used with permission from the National Center for Laboratory and Epidemiology, Ministry of Health, Lao People’s Democratic Republic.
Fig. 2.
Fig. 2.
Reported confirmed diphtheria cases* and estimated coverage** with three doses of diphtheria-containing vaccine (DTP3) among children aged 12–23 months – Lao People’s Democratic Republic, 1980–2013. *Confirmed diphtheria cases reported to the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) through the Joint Reporting Form (JRF), WHO Regional Office for the Western Pacific Region. **WHO/UNICEF estimates of national immunization coverage: http://apps.who.int/immunization_monitoring/globalsummary/incidences?c=LAO.
Fig. 3.
Fig. 3.
The number of reported confirmed diphtheria (N = 62) during April 1, 2012–May 31, 2013 and reported DTP3 administrative coverage (%) in 2012 by province – Lao People’s Democratic Republic.
Fig. 4.
Fig. 4.
Reported confirmed diphtheria cases (N = 62) within and outside Houaphan Province – Lao People’s Democratic Republic, April 1, 2012–May 31, 2013.
See this image and copyright information in PMC

References

    1. Farizo KM et al. Fatal respiratory disease due to Corynebacterium diphtheriae: case report and review of guidelines for management, investigation, and control. Clin Infect Dis 1993;16(1):59–68. - PubMed
    1. Vidor E, Plotkin SA. In: Plotkin S, Orenstein WA, Offitt PA, editors. Vaccine: poliovirus vaccine – inactivated. HongKong, China: Elsevier Saunders; 2013. p. 573–9 [China].
    1. World Health Organization Immunization Vaccines and Biologicals. The immunological basis for immunization series module 2: Diphtheria Update; 2009. Available from: <http://whqlibdoc.who.int/publications/2009/9789241597869_eng.pdf> [Accessed 20 April 2015].
    1. World Health Organization 2006. Position paper on diphtheria. Available from: <http://www.who.int/wer/2006/wer8103.pdf?ua=1> [Accessed 14 April 2015].
    1. Wheeler BS. New trends in diphtheria research. New York: Nova Science Publishers; 2006.

Publication types

MeSH terms

Substances