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Miyano S, Vynnycky E, Pattamavone C, Ichimura Y, Mori Y, Nouanthong P, Phounphenghack K, Tengbriacheu C, Khamphaphongphane B, Franzel L, Yang TU, Raaijimarkers H, Komada K, Ota T, Funato M, Takeda M, Hachiya M. Comparison of population-based measles-rubella immunoglobulin G antibody prevalence between 2014 and 2019 in Lao People's Democratic Republic: Impacts of the national immunization program. Int J Infect Dis 2023; 129:70-77. [PMID: 36758852 DOI: 10.1016/j.ijid.2023.01.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/10/2023] Open
Abstract
OBJECTIVES We evaluated the effectiveness of the Lao People's Democratic Republic's measles-rubella immunization program using the seroprevalence from two cross-sectional surveys. METHODS The nationwide surveys occurred in 2014 and 2019 using a multistage cluster sampling, both requiring samples from 2184 individuals from 52 randomly selected villages. Immunoglobulin G titers, measured using enzyme-linked immunosorbent assay, were considered positive at ≥120 mIU/ml (measles) and ≥10 IU/ml (rubella). We calculated the vaccination-related reduction in the force of rubella infection and the number of congenital rubella syndrome cases averted in 2019. RESULTS We collected 2135 (women: 55.2%, mean age: 23.2 years) and 2001 (52.7%, 23.1 years) samples in 2014 and 2019, respectively. During 2014-2019, immunoglobulin G prevalence increased from 83.9% (95% confidence interval [CI]: 83.8-84.0) to 98.3% (97.7-98.8) for measles and from 75.4% (75.3-75.5) to 87.8% (86.4-89.2) for rubella. The most plausible reduction in the average force of rubella infection was 100% (95% CI: 28-100) since vaccination started, averting 78 (95% CI: 42-128) congenital rubella syndrome cases in 2019. CONCLUSION This is the first population-based study for measles and rubella at two different time points in developing countries. Measles and rubella seroprevalence increased significantly during 2014-2019, greatly exceeding the immunity thresholds for their elimination.
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Affiliation(s)
- Shinsuke Miyano
- Bureau of International Health Cooperation and World Health Organization (WHO) Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Tokyo, Japan.
| | - Emilia Vynnycky
- United Kingdom Health Security Agency, London, UK; London School of Hygiene & Tropical Medicine, London, UK
| | - Chansay Pattamavone
- National Immunization Program, Mother and Child Health Center, Ministry of Health, Lao People's Democratic Republic (Lao PDR), Vientiane, Lao PDR
| | - Yasunori Ichimura
- Bureau of International Health Cooperation and World Health Organization (WHO) Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Tokyo, Japan
| | - Yoshio Mori
- Department of Virology III and WHO Global Specialized Laboratory for Measles and Rubella, National Institute of Infectious Diseases, Tokyo, Japan
| | - Phonethipsavanh Nouanthong
- Institute Pasteur du Laos, National Immunization Technical Advisory Group, Ministry of Health, Lao PDR, Vientiane, Lao PDR
| | - Kongxay Phounphenghack
- National Immunization Program, Mother and Child Health Center, Ministry of Health, Lao People's Democratic Republic (Lao PDR), Vientiane, Lao PDR
| | - Chankham Tengbriacheu
- National Immunization Program, Mother and Child Health Center, Ministry of Health, Lao People's Democratic Republic (Lao PDR), Vientiane, Lao PDR
| | | | - Lauren Franzel
- Vaccine-Preventable Diseases and Immunization Team, WHO Lao PDR, Vientiane, Lao PDR
| | - Tae Un Yang
- Vaccine-Preventable Diseases and Immunization Team, WHO Lao PDR, Vientiane, Lao PDR
| | | | - Kenichi Komada
- Bureau of International Health Cooperation and World Health Organization (WHO) Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Tokyo, Japan
| | - Tomomi Ota
- Bureau of International Health Cooperation and World Health Organization (WHO) Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Tokyo, Japan
| | - Masafumi Funato
- Bureau of International Health Cooperation and World Health Organization (WHO) Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Tokyo, Japan
| | - Makoto Takeda
- Department of Virology III and WHO Global Specialized Laboratory for Measles and Rubella, National Institute of Infectious Diseases, Tokyo, Japan
| | - Masahiko Hachiya
- Bureau of International Health Cooperation and World Health Organization (WHO) Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Tokyo, Japan
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