Table 1: Virus Characteristics.
| Characteristics | Covid-19 | Influenza A | Measles |
| Transmission Route | Respiratory Fomites Oral-Fecal | Respiratory Fomites Oral-Fecal | Respiratory |
| Level of Infectivity | Very contagious | Less contagious | Severly contagious |
| Incubation Period | 2-14 days (median 5.1 days) | 1-4 days (median 2 days) | 10 days to onset of fever; 14 days to onset of rash |
| Risk Factors | Risk factors similar to Covid-19 | Malnutrition, vitamin A deficiency, | |
| Clinical Signs & Symptoms | Fever, cough, chills, myalgia, fatigue, shortness of breath, loss of taste, smell, diarrhea | Fever, cough, chills, myalgia sore throat, nasal congestion | Generalized maculopapular skin rash, fever, cough, rhinitis, conjunctivitis, Koplik spots on mucosa of cheeks otitis media |
| Onset of Clinical Symptoms | Symptoms peak during 2nd to 3rd week of disease | Symptoms peak during 3rd to 7th day of illness | Prodromal phase 2-4 days of fever. Rash develops 2-4 days after fever. Koplik spots appear 1-2 days before onset of rash |
| Reproductive Number | 2 to 4 | 1.5 to 2 | 9 to 18 |
| Case Fatality Rate | 0.25% to 3.0% | 0.10% | < 0.01% to > 5% > 5%, may increase to 20-30% in refugees |
| Diagnostics | PCR testing, serologic testing | PCR testing | Detection of IgM antibodies, PCR testing |
| Antiviral Drugs | Nucleoside analog (Remdesivir) | Neuraminidase inhibitors, endonuclese inhibitors, M2 channel blockers | None |
| Vaccine | Yes | Yes | None |