ABSTRACT
Kenya has experienced five COVID-19 surges driven by Alpha, Beta, Delta (2x), and Omicron. These waves are accurately
predicted by the OTOI-NARIMA model. Consequently, in Kenyan Lake Region
Economic Bloc (LREB), private sector and NGO partnerships have been forged to
strengthen regional health systems and prepare effectively for epidemic
resurgence. The co-development and implementation of the so-called “LREB COVID-Dx” digital platform enable efficient epidemic monitoring in semi-real time,
referral of patients, optimal use of limited resources, and community of
practice among regional health practitioners. In this paper, we describe the
practical implementation of the OTOI-NARIMA model and COVID-Dx digitized
platform in Kenyan COVID-19 reality, with emphasis on the latest Omicron wave. In
estimating the trajectory of Omicron wave, 612 data points of daily case
infections are used. The order of moving
average is calculated and corresponds to reproduction number, R0. The series are normalized, superimposed, and used to derive OTOI-NARIMA
model. The model is estimated and interpreted. Test statistics including Ljung-Box test, ACF, and PACF are conducted. The
COVID-Dx data digitization is used to
inform epidemic preparedness. The OTOI-NARIMA model in general
successfully established the periodicity and seasonality of COVID-19
resurgences in Kenya. The model is used to inform preparedness, including
vaccines rollout. During alert stages of the wave, on December 4, 2021, the
model was reused to nowcast the
trajectory of the wave. Omicron wave was projected to peak in Kenya between
November 23, 2021, and January 4, 2022. The wave showed strong likelihood of
declining after January 29, 2022. In reality, Omicron wave was experienced from
November 27, 2021, to January 29, 2022. The model predicted that Omicron
variant will have run its full course by June 22, 2022, and possibly replaced
by another variant, recombinant or sub-variant. According to OTOI-NARIMA model,
dominant variants are replaced after every six months, which gives insights
into suitable periods for administration of vaccine boosters. The total number
of Kenyan patients (symptomatic or asymptomatic) during Omicron resurgence was
estimated to be ~4.5 million. The total number of patients hospitalized during
the wave is estimated to be ~2000. Effective, efficient, and economical
response to Omicron resurgence in LREB benefitted from meticulous infusion of
mathematical modelling and digitization of relevant data for epidemic
preparedness and rapid decision making. The study has two limitations:
Incomplete merging of stochastic processes and deterministic methods;
calculating with accuracy the period it takes to fully replace a dominant COVID-19
variant. These two limitations may be considered for further research.