The starting dates of COVID-19 multiple waves

Area of Science:

• Epidemiology
• Statistical Modeling
• Public Health

Background:

• The rapid global spread of severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2) caused significant international concern due to the severity of coronavirus disease 2019 (COVID-19).
• Initial detection of COVID-19 in Rio de Janeiro occurred in March 2020, but the precise start of local transmission remains uncertain due to unpreparedness of the Brazilian epidemiological surveillance system.
• Accurately identifying the emergence of new community transmission outbreaks is challenging due to the complex nature of disease spread.

Purpose of the Study:

• To propose a general methodology for determining the start dates of multiple COVID-19 community outbreaks.
• To develop a statistical model capable of describing observed COVID-19 contagion waves.
• To apply this methodology to the COVID-19 dynamics in Rio de Janeiro as a case study.

Main Methods:

• Utilizing a parametric statistical approach.
• Combining epidemiological surveillance data with nonlinear regression techniques.
• Employing information criteria to select the optimal statistical model.

Main Results:

• The developed methodology successfully identified potential start dates for multiple COVID-19 community outbreaks.
• Analysis of COVID-19 dynamics in Rio de Janeiro suggests the original SARS-CoV-2 strain was present as early as late February 2020.
• Evidence points to massive dissemination during the Carnival festivities.

Conclusions:

• The proposed statistical methodology offers a robust approach to identifying the emergence of infectious disease outbreaks.
• The findings suggest an earlier circulation of SARS-CoV-2 in Rio de Janeiro than previously confirmed.
• Public health interventions and surveillance strategies should consider potential early introduction and rapid dissemination events, especially during large public gatherings.