Effectiveness of COVID-19 Vaccine Boosters in Indonesia

Funder
US Centers for Disease Control and Prevention

Principal Investigators
Bayu Satria Wiratama
Associate Professor Raph Hamers

Locations
Jakarta and Yogyakarta, Indonesia

Duration
August 2022 – September 2023

This study aims to investigate the real-world effectiveness of vaccinations, including booster doses, against symptomatic COVID-19 among the general population in Indonesia.

Background

Vaccine-induced population immunity is a key global strategy to control the COVID-19 pandemic, and to date ten COVID-19 vaccines have received Emergency Use Listing (EUL) by the WHO. Indonesia has been one of the global epicenters of the COVID-19, only behind India in the Asian region.

By October 2022, the reported total number of Indonesian people infected with SARS-CoV-2 is 6.5 million people, and the death toll has reached 158,000. In Indonesia, vaccination roll-out was initiated in January 2021, and vaccine coverage has been estimated at 100% and 40% for second and third dose, respectively.

Most people received primary vaccination with inactivated vaccine (Coronavac/SinoVac), or, in lesser numbers, viral vector (ChAdOx1-S/AstraZeneca), or mRNA vaccines (BNT162b2/Pfizer-BioNtech or m1273/Moderna).

A lot of uncertainty remains around which vaccines are the most effective, how many doses are needed to induce long-term immunogenicity, what is the role of natural infection, and whether homogenous or heterogenous vaccine combinations confer better protection.

One of the specific challenges with the rapid emergence of novel SARS-CoV-2 variants is whether the available vaccines and booster regimens confer optimal protection against the new variants.

There has been limited scientific evaluation of the effectiveness of the Government of Indonesia vaccine programme, including the various heterologous booster combinations, especially in the face of Omicron emergence.

Aims

Adopting a test-negative design (TND) case-control design the study will recruit adults with symptoms suspect of COVID-19 at selected laboratory and hospital sites in Jakarta and Yogyakarta.

Objectives are to evaluate vaccine effectiveness against laboratory-confirmed symptomatic COVID-19 comparing 3 and 2 doses of COVID-19 vaccine (and other numbers of doses) among the general adult population; evaluate vaccine effectiveness against severe COVID-19, hospitalisation due to COVID-19, COVID-19 associated death and against different COVID-19 (sub)variants, and evaluate the key determinants of vaccine effectiveness.