Sustaining effective COVID-19 control in Malaysia through large-scale vaccination

Area of Science:

• Epidemiology
• Mathematical modeling of infectious diseases
• Public health interventions

Background:

• Malaysia experienced a COVID-19 resurgence in June 2021.
• Non-pharmaceutical interventions (NPIs) and a vaccination campaign were implemented.
• Limited population immunity heightened susceptibility to resurgence.

Purpose of the Study:

• To assess the potential of the COVID-19 vaccination campaign to control the epidemic in Malaysia.
• To evaluate various public health response scenarios.
• To analyze the impact of vaccination strategies and mobility restrictions.

Main Methods:

• A modified susceptible-exposed-infectious-recovered (SEIR) compartmental model was developed.
• The model incorporated age stratification, population mobility, and variants of concern (VoC).
• Scenarios included different vaccination strategies and mobility restrictions.

Main Results:

• Models fit notification data but underestimated ICU occupancy and deaths.
• Projections indicated a major epidemic if NPIs were fully relaxed at current vaccination rates.
• Incomplete case detection and VoC severity may explain discrepancies.

Conclusions:

• Micro-distancing and sustained mobility restrictions are crucial during vaccination roll-out.
• Accelerating the vaccination pace is essential for future epidemic control.
• Malaysia remains vulnerable to resurgence due to low population immunity.