Combating New COVID-19 Variants in Indonesia: Is Accelerating Four-Dose Vaccinations Sufficient?

TL;DR

This study uses a mathematical model to assess if accelerating four-dose COVID-19 vaccinations in Indonesia can sufficiently mitigate transmission risks from new variants, highlighting the need for additional interventions.

Contribution

It develops an SISI-type model to evaluate vaccination acceleration effectiveness against emerging COVID-19 variants in Indonesia.

Findings

Vaccination acceleration alone is insufficient in high-transmission scenarios.

Significant acceleration is required for low-transmission cases to be effective.

Additional measures like improving vaccine efficacy are recommended.

Abstract

As new COVID-19 variants continue to emerge globally, we develop an SISI-type mathematical model to determine whether the transmission risks arising when such a new variant enters Indonesia can be mitigated by solely accelerating the country's ongoing four-dose vaccination programme. We begin by determining the model's basic reproduction number, as well as the model's equilibria and their stability. Subsequently, employing parameter values representing the country's situation as of March 20, 2023, we conduct a numerical sensitivity analysis in two simulated cases corresponding to two different levels of the new variant's transmission. The results show that, a satisfactory mitigation relying solely on vaccinations necessitates a drastic acceleration in the low-transmission case, and proves unachievable in the high-transmission case. Accordingly, we recommend that the acceleration of the ongoing four-dose vaccinations be carried out in conjunction with other intervention measures, such as improvements of the vaccine's efficacy and the disease's recovery rate.