Epidemiological Investigation of COVID-19 in Laos Using a One-Health Approach in Human and Animals (LACOVISS)
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ClinicalTrials.gov Identifier: NCT04716543 |
Recruitment Status :
Not yet recruiting
First Posted : January 20, 2021
Last Update Posted : July 1, 2021
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The Respiratory infection COVID-19, due to a new coronavirus, SARS-CoV2, appeared in December 2019 in several people who attended the wildlife market in Wuhan, Hubei Province, China. While COVID-19 has spread to nearly 200 countries and caused two millions infections, Lao PDR detected its first confirmed case very recently, on March 20, three months after the start of the outbreak in China. As of April 12th, 2020, Lao PDR has only recorded 18 confirmed cases, a very low number compared to other countries around the world.
However, several key factors suggest that Lao PDR could be much more affected by COVID-19 because of the following reasons: (i) The multiple and massive trans-border movements between Lao PDR and China. (ii) The similar biogeographical and socio-ecological characteristics with South-Western China. (iii) The detection of a high diversity of Betacoronavirus sequences in several species of bats in Lao PDR. (iv) The numerous markets selling high volumes of local wildlife including bats and pangolins.
LACOVISS project aim at investigating, using a ONE-HEALTH approach, this unexpected epidemiological pattern of SARS-CoV-2 in Lao PDR by bringing together an interdisciplinary team of experts in the field from IRD, the University of Caen, the Center of Infectiology Lao-Christophe Mérieux (CILM) and the National animal Health Laboratory (NAHL) in Vientiane. The study will focus on a community-based cohort of 1092 households, including 5400 study participants, followed-up between March 2015 and February 2019 for influenza-like illness investigation and causative agents detection (LACORIS project), located in the Vientiane metropolitan area. The COVID-19 progression in Lao PDR, and track SARS-CoV-2, will be followed retrospectively and prospectively, in all potential actors in SARS-CoV-2 circulation, including humans, domestic animals, and wildlife.
The LACOVISS project will undoubtedly bring new insight in SARS-Cov-2 and SARS-CoV-like circulation in Lao PDR as well as valuable information on the natural history of COVID-19, and on the modalities of the spillover into humans, which are still largely unknown.
Condition or disease | Intervention/treatment |
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Influenza -Like Illness Covid19 | Diagnostic Test: ILI and COVID-19 detection |

Study Type : | Observational |
Estimated Enrollment : | 5400 participants |
Observational Model: | Cohort |
Time Perspective: | Prospective |
Official Title: | One-health Approach in Epidemiological Investigation of SARS-CoV-2 in Laos |
Estimated Study Start Date : | August 1, 2021 |
Estimated Primary Completion Date : | March 2022 |
Estimated Study Completion Date : | March 2022 |

Group/Cohort | Intervention/treatment |
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ILI Investigation
The suspected ILI cases will be first identified using the WHO clinical case definition of ILI and Covid 19 as either with:Acute onset of fever (> 37.5˚C axillary temperature or > 38˚C tympanic temperature) AND cough; OR Acute onset of ANY ONE OR MORE of the following signs or symptoms: Fever, cough, general weakness/fatigue, headache, myalgia, sore throat, coryza, dyspnoea, anosmia (loss of smell) or ageusia (loss of taste); with symptoms with onset within the last 10 days.
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Diagnostic Test: ILI and COVID-19 detection
All participants presenting with ILI symptoms will have non-invasive exam for SARS-CoV-2 detection (nasal, throat, swab, saliva) and a questionnaire. All family members more than 6 months living with SARS-CoV-2 positive individuals will have will have non-invasive exam for SARS-CoV-2 detection (nasal, throat, swab, saliva) and a questionnaire. |
- Prevalence of SARS-CoV-2 RNA in respiratory samples collected from influenza-like illness patients from cohort study 2020-2021 [ Time Frame: Months 12 ]Number of participants SARS-CoV-2 positive among total number of participants tested
- Prevalence of SARS-CoV-2 RNA in respiratory samples from influenza-like illness patients from cohort study between 2015 and 2019 [ Time Frame: Months 12 ]Number of respiratory samples positive for SARS-CoV-2 over the total number of respiratory samples from the 2015-2019 cohort
- Prevalence of SARS-CoV-2 RNA in respiratory samples from intrafamilial contacts of influenza-like illness patients (2020-2021) [ Time Frame: Months 12 ]Number of SARS-CoV-2 positive samples among the total number of samples collected from participants living within the family nucleus of influenza-like illness patients
- Prevalence of SARS-CoV-2 IgG among 1000 individuals randomly selected from the 2020-2121 study cohort. IgG will be assayed in saliva samples [ Time Frame: Months 12 ]Number of participants IgG positive over a thousand, randomly selected, participants tested.
- Prevalence of SARS-CoV-2 RNA in respiratory and faecal samples collected from companion animals living with influenza-like illness patients [ Time Frame: Months 12 ]Number of pet animals positive for SARS-CoV-2 over the total number of pets tested
Biospecimen Retention: Samples Without DNA

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Ages Eligible for Study: | 6 Months and older (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Sampling Method: | Non-Probability Sample |
All permanent residents of the household who meet the inclusion criteria of > 6 months old and living in their respective village for at least 6 months will be eligible to participate. All people from the anterior LACORIS study (2015-2019), will be invited to participate to the study.
Over a year, active case finding for influenza-like illness (ILI) will be conducted among the cohort by staff at CILM. The suspected ILI cases will be first identified using the WHO clinical case definition of ILI and Covid 19 as either with:
Acute onset of fever (> 37.5˚C axillary temperature or > 38˚C tympanic temperature) AND cough; OR Acute onset of ANY ONE OR MORE of the following signs or symptoms: Fever, cough, general weakness/fatigue, headache, myalgia, sore throat, coryza, dyspnoea, anosmia (loss of smell) or ageusia (loss of taste).
with symptoms with onset within the last 10 days.
Inclusion Criteria:
- Living in their respective village for 6 months or more.
- Physically reside in the village for more than 80% of the time during the duration of the study.
- Study subjects ≥ 6 months of age (no upper age limit).
- Consent form signed by patient, or if under 18 years of age or patients with learning difficulty or other vulnerability with impaired ability to decide on consent, signed by parent or guardian.
- Agrees to comply with study requirements.
Exclusion Criteria:
- Study subjects under the age of 6 months.
- Study subjects or parents/guardians that do not accept participation.
- Study subjects or parents/guardians who refuse to sign informed consent.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04716543
Contact: Eric M LEROY, DVM, PhD | +33 467416107 | eric.leroy@ird.fr | |
Contact: Sabrina LOCATELLI, PhD | +33 680596357 | sabrina.locatelli@ird.fr |
Principal Investigator: | Phimpha PABORIBOUNE, MD, PhD | Centre d'Infectiologie Lao-Christophe Mérieux |
Responsible Party: | ANRS, Emerging Infectious Diseases |
ClinicalTrials.gov Identifier: | NCT04716543 |
Other Study ID Numbers: |
ANRS COV20 LACOVISS |
First Posted: | January 20, 2021 Key Record Dates |
Last Update Posted: | July 1, 2021 |
Last Verified: | June 2021 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
SARS-CoV-2 Lao PDR One Health virus coronavirus |
reservoir animal antibody serology PCR |
COVID-19 Respiratory Tract Infections Infections Pneumonia, Viral Pneumonia Virus Diseases |
Coronavirus Infections Coronaviridae Infections Nidovirales Infections RNA Virus Infections Lung Diseases Respiratory Tract Diseases |