According to data published by Ministry of Health and Family Welfare
Graph source: Data from Worldometer
About the Disease
- Incubation Period (time from exposure to the development of symptoms)
- According to WHO, incubation period of the virus is estimated to be between 2 and 14 days and on average 5.2 days.
- It can vary among patients.
- As per WHO, a very long incubation period could represent a double exposure
- Importance of incubation period: Knowing the incubation period is important for health authorities as it help in providing more effective quarantine systems for people suspected of carrying the virus, as a way of controlling and hopefully preventing the spread of the virus.
Comparison with other viruses:
|Novel Coronavirus (COVID-19)
|2–14 or 0–24 days
|5 days (range: 2–14)
|2–7 days, as long as 10 days
|2 days (1–4 range)
|1–4 days, as long as 7 days
- Typically results in flu-like symptoms including fever and cough
- Begins with a fever, followed by a dry cough and after a week results in shortness of breath(approx. 20% patients require hospital treatment)
- Sneezing, sore throat and running nose (rarely).
- Sneezing, stuffy nose and sore throat are usually signs of a cold
- Pre-existing illnesses: Patients with pre-existing conditions like: Cardiovascular disease, diabetes, chronic respiratory disease and hypertension are more vulnerable for the disease
- It may present with mild, moderate, or severe illness that includes severe pneumonia, Acute Respiratory Distress Syndrome, sepsis and septic shock.
- Mild to moderate disease: 80% includes pneumonia and non-pneumonia cases
- Severe disease: 13.8% includes dyspnea, respiratory frequency ≥30/minute, blood oxygen saturation ≤93%, PaO2/FiO2 ratio <300, and/or lung infiltrates >50% of the lung field within 24–48 hours
- Critical cases: 6.1% (respiratory failure, septic shock, and/or multiple organ dysfunction/failure)
Based on report of WHO-China Joint Mission on COVID 19
Coronavirus, Flu, Cold or Allergy:
- Symptoms of COVID-19 ranges from no symptoms to severe pneumonia and death.
- Following are the symptoms of COVID-19 and their comparison with flu, cold and seasonal allergies.
Source: WHO, CDC, NBC
Something else or COVID 19
Effect of COVID-19 on Lungs:
- Infection of the respiratory tree results in inflammation of the lining of respiratory tree. This causes irritation of the nerves present in the lining of the airway.
- Sometimes, infection reaches to the gas exchange unit present at the end of air passages. This results in collection of inflammatory material into the air sacs present at the bottom of the lungs and inflammation of air sacs results in outpouring of inflammatory material into the lungs causing pneumonia.
Transmission and spread
- Transmission of COVID-19 during unprotected and close contact between an infector and infectee is via droplets and fomites.
- No evidence of airborne spread however it has been predicted that certain aerosol-generating procedures conducted in health care facilities may be responsible for the spread of virus.
- According to research, the high affinity of the 2019-nCoV S for human ACE2 may act as a factor for human-to human transmission but further studies are needed to investigate this possibility.
- The virus can remain viable and infectious for hours to days on surfaces.
- The virus remains infectious for up to three days on plastic and stainless steel, for one day on cardboard, and for up to four hours on copper.
- Solutions like: 62–71% ethanol, 50–100% isopropanol, 0.1% sodium hypochlorite, 0.5% hydrogen peroxide and 0.2–7.5% povidone-iodine may be used for disinfection.
Detection of the Virus
Laboratory testing for COVID-19 virus:
- National guidelines are formulated on laboratory biosafety.
- Molecular testing of specimen requires BSL-2 or equivalent facilities and labs designed for viral culture require BSL-3 facilities at minimum.
- Nucleic acid amplification tests (NAAT): Used for routine confirmation of cases of COVID-19. Detection of unique sequences of virus RNA by NAAT such as real-time reverse-transcription polymerase chain reaction (rRT-PCR) is with confirmation by nucleic acid sequencing if necessary.
- Serological testing: For investigation of outbreak and retrospective assessment of the attack rate or extent of an outbreak.
- Viral sequencing: Used for monitoring of viral genome mutation that might affect the performance of medical countermeasures, including diagnostic test.
- Viral culture
Dr Swati Mehra