Forecasted Trends of the New COVID-19 Epidemic Due to the Omicron Variant in Thailand, 2022

Abstract

Thailand is among many countries severely affected by COVID-19 since the beginning of the global pandemic. Thus, a deliberate planning of health care resource allocation against health care demand in light of the new SARS-CoV-2 variant, Omicron, is crucial. This study aims to forecast the trends in COVID-19 cases and deaths from the Omicron variant in Thailand. We used a compartmental susceptible-exposed-infectious-recovered model combined with a system dynamics model. We developed four scenarios with differing values of the reproduction number (R) and vaccination rates. In the most pessimistic scenario (R = 7.5 and base vaccination rate), the number of incident cases reached a peak of 49,523 (95% CI: 20,599 to 99,362) by day 73, and the peak daily deaths grew to 270 by day 50. The predicted cumulative cases and deaths at the end of the wave were approximately 3.7 million and 22,000, respectively. In the most optimistic assumption (R = 4.5 and speedy vaccination rate), the peak incident cases was about one third the cases in the pessimistic assumption (15,650, 95% CI: 12,688 to 17,603). In the coming months, Thailand may face a new wave of the COVID-19 epidemic due to the Omicron variant. The case toll due to the Omicron wave is likely to outnumber the earlier Delta wave, but the death toll is proportionately lower. Vaccination campaigns for the booster dose should be expedited to prevent severe illnesses and deaths in the population.

Booster Dose Vaccination and Dynamics of COVID-19 Pandemic in the Fifth Wave: An Efficient and Simple Mathematical Model for Disease Progression

“…Although their model was very promising, comparison with real-world data was not evident, and the authors did not present vital parameters, such as specific analysis for hospitalization, recovery, and deaths, as in our study. Suphanchaimat et al did include booster vaccine doses, but their study, though it made impressive forecasts, lacked the effect of individual vaccine doses and validation with real-world data [ 28 ]. In our study, keeping the model as simple and straightforward as possible was a primary concern because mathematical models are known to use a plethora of convoluted and superfluous parameters and equations.…”

The Principles of SARS-CoV-2 Intervariant Competition Are Exemplified in the Pre-Omicron Era of the Colombian Epidemic

“…The growth advantage (ρ) estimated in the applied model is linked to various intrinsic factors, including an increase in transmissibility (τ, which may also be linked to an increase in peak viral load), increase in infectious duration (κ), enhanced immune evasion behavior (ε, which can vary from complete cross-protection, ε = 0, to full evasion, ε = 1, as defined previously [ 17 ]), or some combination of all. As previously assumed ( 18 , 19 ), we consider κ to be identical between all lineages in question due to numerous studies citing the inability to culture replication-competent virus from patient specimens obtained after 10 days post-symptom onset ( 20 – 24 ). Thus, an interplay between τ and ε will affect ρ. Additionally, if ε does indeed play a role, its contribution strongly depends on the assumed level of population seroprevalence (Ω) against the virus through previous infection or vaccination.…”

Combined Impact of Omicron Vaccination and Environmental Risk Exposure: A Thailand Case Study

“…The Omicron variant of the COVID-19 epidemic outbreak also caused rapid transmission with populations in many countries including the United States [ 41 ], the United Kingdom [ 42 ], and South Africa [ 43 ]. In the context of Thailand, Suphanchaimat et al [ 23 ] investigated the peak and daily death number of COVID-19 Omicron variant incidents. The low rate of COVID-19 vaccination was 49,523 cases by day 73 and over 270 by day 50, respectively.…”

“…The Thai Ministry of Public Health (MOPH) reported and confirmed the first case of the Omicron variant in early December 2021. This situation caused significant concern for the government regarding the capacity of the Thai healthcare system to handle the new variant outbreak [ 23 ]. In Thailand, two groups of vaccines are fully registered and approved by the Ministry of Public Health for emergency use: (1) free-of-charge vaccines including Sinovac, Pfizer, and AstraZeneca and (2) pay-by-yourself vaccines including Sinopharm and Moderna [ 24 ].…”