Part 4/12:
Initially, it was uncertain whether the virus spread solely from animals to humans or could transmit from person to person. The presence of cases linked to the Wuhan seafood market suggested zoonotic origin, but as reports of human-to-human transmission grew, fears intensified. By January 20, data confirmed that sustained human transmission was occurring, elevating the risk from localized outbreak to a potential global pandemic.
Public health responses shifted accordingly, with measures like temperature screening at airports and heightened vigilance among clinicians. The realization that COVID-19 was a respiratory disease meant it spread via droplets—expelled when infected individuals coughed or sneezed—and could be transmitted through contact with contaminated surfaces.