Differentiating Contact with Symptomatic and Asymptomatic Infectious Individuals in a SEIR Epidemic Model

This manuscript introduces a new Erlang-distributed SEIR model. The model incorporates asymptomatic spread through a subdivided exposed class, distinguishing between asymptomatic ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>E</mml:mtext> <mml:mi>a</mml:mi></mml:msub> </mml:math> ) and symptomatic ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>E</mml:mtext> <mml:mi>s</mml:mi></mml:msub> </mml:math> ) cases. The model identifies two key parameters: relative infectiousness, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>β</mml:mi> <mml:mrow><mml:mi>SA</mml:mi></mml:mrow> </mml:msub> </mml:math> , and the percentage of people who become asymptomatic after being infected by a symptomatic individual, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>κ</mml:mi></mml:math> . Lower values of these parameters reduce the peak magnitude and duration of the infectious period, highlighting the importance of isolation measures. Additionally, the model underscores the need for strategies addressing both symptomatic and asymptomatic transmissions.