Lao – Lux lab / Vaccine preventable diseases 2023

Head of Laboratory:  Dr. Antony BLACK

The vaccine-preventable disease laboratory has been conducting research on infectious diseases in Laos since 2011. The laboratory’s research objectives are:

• To investigate the epidemiology of infectious diseases in humans and animals, with a focus on vaccine-preventable diseases.
• To provide health officials with the scientific evidence required for their decisions to improve human and animal health.
• To evaluate and strengthen current disease prevention and control measures, including vaccination programs.
• To build qualitative and sustainable laboratory capacity.

The results and recommendations of the studies are communicated to stakeholders and partners in the form of written and oral reports and policy briefs.

Executive summary.

The Vaccine-preventable disease (VPD) laboratory has a remit to build capacity for investigations of human and animal infectious diseases that are of relevance for Lao PDR. Our activities are in collaboration with the Clinical and Applied Virology group at the Luxembourg Institute of Health (LIH), Luxembourg, headed by Judith Hübschen. We work closely with local partners and focus on the epidemiology and seroprevalence of vaccine-preventable infectious diseases, as well as animal and zoonotic diseases. As such, we can provide stakeholders in human and animal health with estimates of the burden of infections, promote outbreak control and vaccination programs, and propose measures to optimize national health strategies. Our evidence-based results and recommendations are communicated to stakeholders and partners in the form of written and oral reports and policy briefs. In this year’s report, we detail several completed and ongoing studies.

Early in 2023, the team visited Khammouane province for a 3-month fieldwork mission. This project aims to evaluate the relationship between water, sanitation and hygiene (WASH) and infectious diseases. To this end, the team collected data on household and individual WASH levels, as well as the history of infections and biological samples (stool and serum). Laboratory analysis and data interpretation are ongoing for this project, which forms a part of Vilaysone Khounvisith’s PhD studies, in collaboration with the Swiss Tropical and Public Health Institute and the Lao Tropical and Public Health Institute.

Healthcare workers represent an important “at-risk” population for several infectious diseases. Hepatitis B virus (HBV) is one such disease, and HCWs have the risk of infection from contaminated blood exposure, for example by needle-stick injuries. There is also a risk of transmission of the virus from infected HCWs to patients under their care. Despite worldwide recommendations to administer 3 doses of the HBV vaccine, it is not routine in Laos. We therefore carried out a serological study to evaluate the protection and exposure of healthcare workers against HBV. We present a summary of the results in this report.

Proper adherence to the infant HBV vaccination schedule is essential to prevent early exposure to the virus. Indeed, early exposure is strongly linked to a risk of developing chronic infection and subsequent liver disease. Laos introduced the birth dose and the three subsequent doses of HBV vaccine around 20 years ago, however, achieving high vaccine coverage has remained difficult. We performed a study analyzing patterns and determinants of HBV vaccine coverage by using data that were collected in the context of the Lao multiple indicator cluster surveys (MICS). These surveys cover data including household wealth, education, and health and allow us to compare vaccine coverage in different years, as well as associations with different factors.

Tetanus and diphtheria are two vaccine-preventable bacterial diseases. In many countries, adolescents receive booster doses for both. However, in Laos, there is no such policy. We wished to determine the serological protection in Lao adolescents against these important diseases. In the current report, we show our data that indicate low seroprotection in Lao adolescents.

Plain language summary.

Our laboratory focuses on research into infectious diseases and equality of health in Laos. This year we have ongoing studies related to parasites and infectious diseases that are spread by poor water, sanitation, and hygiene. We investigated the commonness of these diseases in rural settings, with an aim to inform policymakers about the link between such infectious diseases and the environment. We also investigated the impact on the health of hepatitis B virus in Lao healthcare workers. These individuals are particularly at risk of infection with this virus and subsequent liver disease due to exposure to contaminated blood. Our data will highlight the level of infection and protection in this important group and suggest ways to reduce the risk such as by administration of the effective hepatitis B vaccine. In addition, we completed a separate study where we analyzed data to determine the level of infant hepatitis B vaccine coverage. We identified addressable factors that may impact vaccination coverage in Lao infants. Finally, we show data on Lao adolescent susceptibility to two important bacterial diseases – tetanus and diphtheria. Low protection against these two diseases strongly suggests that booster doses of the vaccines are warranted in Laos.


Dr. Siriphone Virachith, MD, PhD

Junior scientist, PhD student:
Dr. Vilaysone Khounvisith, PhD student

Laboratory technician:
Mrs. Latdavone Khenkha
Mrs. Bounta Vongphachanh
Mrs. Nouna Innoula

Dr. Phonethipsavanh Nouanthong, MD

Trainee (Arboshield project):
Mrs. Souksan Sihuksa
Mrs. Phimphone Sisomphone

LIH Luxembourg:

Senior Consultant:
Dr. Judith Hübschen, PhD

Postdoctoral fellow, visiting scientist:
Dr. Lisa Hefele, PhD

PhD student, visiting:
Mrs. Andrea Diaz

Project carried on in the lab:

+Tetanus and diphtheria seroprotection in Lao adolescents.
+Water, sanitation and hygiene (WASH); relationship with infectious diseases.
+Hepatitis B virus exposure, vaccination status and susceptibility in Healthcare Workers from Lao PDR.
+Factors associated with hepatitis B vaccination in the Lao People’s Democratic Republic: findings from the Multiple Indicator Cluster Surveys in 2011/12 and 2017.