“The outbreak was first reported on December 31, 2019…”

Transmission of COVID-19

Animal-to-human transmission

The virus may have originated from an unknown animal source, with early cases linked to direct exposure.

Human-to-human transmission

Transmission occurs through:

• Respiratory droplets (>5 microns)
• Direct contact
• Contaminated surfaces
• Close proximity (up to 2 meters)

Incubation period

• Average: 5–6 days
• Range: 0–24 days

Duration of disease

• Mild: 2 weeks
• Severe: 3–6 weeks

Reproduction number and transmission

• R0: 2–3
• Reduced with public health measures

Community and hospital transmission

• High initial infection among healthcare workers
• Reduced with protective equipment

Severity and mortality

• Approx. 3% mortality in China
• Higher in hospitalized patients

Asymptomatic cases

• Around 1–18% depending on cohort

Symptoms

• Fever
• Dry cough
• Flu-like symptoms

Pediatric cases

• Lower incidence
• Mostly mild or asymptomatic

Risk groups

• Elderly
• Chronic diseases
• Immunocompromised

Vaccines

• Development timeline: 18–24 months

Prevention measures

• Mask use
• Hand hygiene
• Social distancing
• Pediatric support:
  • Vaccination
  • Nutrition
  • Immune support

Document prepared by Octavio Davila | Scientific Director