Arkell P

Sheridan S

Martins N

Tanesi M

Gomes N

Amaral S

Oakley T

Solano V

David M

Draper, Anthony

Sarmento N

da Silva E

Alves L

Freitas C

Machado F

Gusmão C

da Costa Barreto I

Fancourt N

Macartney K

Yan, Jennifer

Francis, Joshua

2023-05-01

INTRODUCTION: Historic disruption in health infrastructure combined with data from a recent vaccine coverage survey suggests there are likely significant immunity gaps to vaccine preventable diseases and high risk of outbreaks in Timor-Leste. Community-based serological surveillance is an important tool to augment understanding of population-level immunity achieved through vaccine coverage and/or derived from prior infection. METHODS AND ANALYSIS: This national population-representative serosurvey will take a three-stage cluster sample and aims to include 5600 individuals above 1 year of age. Serum samples will be collected by phlebotomy and analysed for measles IgG, rubella IgG, SARS-CoV-2 antispike protein IgG, hepatitis B surface antibody and hepatitis B core antigen using commercially available chemiluminescent immunoassays or ELISA. In addition to crude prevalence estimates and to account for differences in Timor-Leste's age structure, stratified age-standardised prevalence estimates will be calculated, using Asia in 2013 as the standard population. Additionally, this survey will derive a national asset of serum and dried blood spot samples which can be used for further investigation of infectious disease seroepidemiology and/or validation of existing and novel serological assays for infectious diseases. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the Research Ethics and Technical Committee of the Instituto Nacional da Saúde, Timor-Leste and the Human Research Ethics Committee of the Northern Territory Department of Health and Menzies School of Health Research, Australia. Co-designing this study with Timor-Leste's Ministry-of-Health and other relevant partner organisations will allow immediate translation of findings into public health policy, which may include changes to routine immunisation service delivery and/or plans for supplementary immunisation activities.

Global and Tropical Health Division, Menzies School of Health Research Timor-Leste Office, Dili, Timor-Leste paul.arkell@menzies.edu.au.

National Centre for Immunisation Research and Surveillance (NCIRS), Westmead, New South Wales, Australia.

Global and Tropical Health Division, Menzies School of Health Research Timor-Leste Office, Dili, Timor-Leste.

Faculty of Science and Technology, Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia.

The Daffodil Centre, The University of Sydney, Sydney, New South Wales, Australia.

School of Medicine and Dentistry, Griffith University, Brisbane, Queensland, Australia.

Centre for Disease Control, Northern Territory Department of Health, Casuarina, Northern Territory, Australia.

National Centre for Epidemiology and Population Health, Australian National University, Canberra, Northern Territory, Australia.

Laboratório Nacional da Saúde, Timor-Leste Ministry of Health, Dili, Timor-Leste.

Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia.

Departemento Vigilancia e Epidemiologia, Timor-Leste Ministry of Health, Dili, Timor-Leste.

Department of Internal Medicine, Hospital Nacional Guido Valadares, Dili, Timor-Leste.

Health System Strengthening Department, World Health Organisation, Timor-Leste Office, Dili, Timor-Leste.

Department of Paediatrics, Royal Darwin Hospital, Darwin, Northern Territory, Australia.

BMJ Open. 2023 May 18;13(5):e071381. doi: 10.1136/bmjopen-2022-071381.

0000-0003-3702-2716

0000-0002-4675-0232

0000-0001-9302-4543

https://pubmed.ncbi.nlm.nih.gov/37202138/?otool=iaurydwlib

https://hdl.handle.net/10137/12465

13

Humans

Seroepidemiologic Studies

Timor-Leste/epidemiology

Cross-Sectional Studies

*Vaccine-Preventable Diseases

*COVID-19/epidemiology/prevention & control

SARS-CoV-2

Immunoglobulin G

Northern Territory

Vaccine Preventable Disease Seroprevalence in a Nationwide Assessment of Timor-Leste (VASINA-TL): study protocol for a population-representative cross-sectional serosurvey.

Journal Article

Publication