Background:

According to the Viet Nam Ministry of Health, as of 4th April 2021, Viet Nam has received nearly one million doses of the AstraZeneca COVID-19 vaccine. Accordingly, a total of 52,335 frontline healthcare workers from 19 provinces/cities across the country have received their first doses. As yet, none in Viet Nam has received a second dose of the COVID-19 vaccine.

At the Hospital for Tropical Diseases (HTD) in Ho Chi Minh City, a total of 894 members of staff received their first doses of the AstraZeneca COVID-19 vaccine during the second week of March 2021. Yet, there has been no reported data regarding the immunogenicity of COVID-19 vaccines and the associated adverse events in Vietnamese people. Likewise, it remains unknown regarding the extent to which seasonal coronaviruses might interact with the immune landscape generated by the COVID-19 vaccine and vice versa.

The emergence of variants of concerns (B.1.1.7, P1 and B.1.135) of SARS-CoV-2 emphasises the importance of active surveillance for SARS-CoV-2 variants worldwide. Of equal importance is to assess the immune escape potential of such novel variants. These are now the top priorities of the WHO and the public health authorities of countries across the globe.

Collectively, to inform the global vaccination programme, we aim to fill some important existing gaps in knowledge about the immunogenicity of the AstraZeneca COVID-19 vaccine in Vietnamese healthcare workers and the adverse events that might arise within 48 hours after vaccination. More specifically, our primary aims are to determine the development of detectable neutralising antibodies after vaccination (first and second doses) and the durability of neutralising antibodies for a period of 12 months after vaccination. Additionally, to inform the public about the safety of the AstraZeneca COVID-19 vaccine, we will also synthesisedata on the associated adverse events occurring within 48 hours after vaccination. This 48-hour window time was determined by the Vietnamese Ministry of Health.

Primary Objectives:

• To determine the development of detectable neutralising antibodies to SARS-CoV-2 at 14 and 28 days after the first dose of AstraZeneca COVID-19 vaccine in Vietnamese healthcare workers.
• To assess the durability and kinetic of neutralising antibodies against SARS-CoV-2 in Vietnamese people over 12 months after vaccination.
• To describe the adverse events arising within 48 hours after receiving the AstraZeneca COVID-19 vaccine, allied with the development of neutralising antibodies at 14 and 28 days after the first dose and 14 days after the second dose.

Secondary Objectives:

• To assess the impact of the second dose on the titers of neutralizing antibodies to SARS-CoV-2 at 14 days after the administration.
• To record SARS-CoV-2 infection events (if any) and the associated clinical features in Vietnamese people after receiving the AstraZeneca COVID-19 vaccine.
• To assess the T cell response against SARS-CoV-2 in Vietnamese people after receiving AstraZeneca COVID-19 vaccine and (if relevant) the immune escape potential of new SARS-CoV-2 variants.
• To assess the cross-reactivity between immunity induced by AstraZeneca COVID-19 vaccine and common cold coronaviruses (NL63, OC43, 229E and HKU1).

Importance

The Africa Asia Programmes (including OUCRU) have recently been funded by Wellcome to strengthen the whole-genome sequencing capacity and to conduct active surveillance for SARS-CoV-2 variants in their respective host countries. Therefore, if relevant, we will use the collected PBMC and plasma samples of the present study to assess the immune escape potential of new variants of SARS-CoV-2.

Collectively, the present study forms a part of our holistic effort on SARS-CoV-2 evolution and immunity in Viet Nam and the region. As such, the obtained data are critical to informing the local, regional and global vaccination programme and the associated COVID-19 research.

From the public engagement perspective, it is also critical to demonstrate that the AstraZeneca COVID-19 vaccine is safe and effective. This project will provide data on the common side effects of the vaccine, and we will work with the HTD and OUCRU Public Engagement team to identify the best communication channels for this important data.