Figure 3. Case fatality rate amongst people in hospital with COVID-19 from New York. Image credit: J. Glynn, adapted from data in 5
What happens if someone gets infected?
Once infected, symptoms take 5-6 days to appear, though in some people the lag is up to 14 days.
The initial infection in the upper airways may give no symptoms or may be accompanied by cough, fever, head and body aches, sore throat and loss of sense of smell. The virus multiplies in the upper airways so people are infectious i.e. they
can transmit the infection. Some people have gut involvement giving diarrhoea.
In some people the infection may progress down into the lungs giving pneumonia. The body’s immune response causes inflammation in the lungs which reduces the amount of oxygen that can be absorbed, leaving the patient short of breath. Some
patients recover on their own from this, some will need oxygen to tide them over until their body manages to deal with the virus, but some get much worse and develop acute respiratory distress syndrome (ARDS). In ARDS there
is so much inflammation in the lungs that oxygen cannot get through. Artificial ventilation is usually needed and some patients will die.
In the small minority of patients with very severe disease, there is a risk that almost all other organs in the body can also be affected (not just the lungs). Damage can be done both by the virus, or by the body’s response to it. This can
lead to blood clots and constriction (tightening) of blood vessels, which limit blood supply to organs. There can also be direct damage to the heart and kidneys. And some patients have had strokes or seizures or confusion with brain inflammation.
Recovery can take around 2 weeks in cases of mild disease, but in instances of severe disease, symptoms may continue for up to 8 weeks2, and for a small proportion of people there may be long-term complications.
ARDS: Acute Respiratory Distress Syndrome: A life-threatening condition in which lungs become inflamed, and breathing becomes difficult.
Artificial Ventilation: The use of machines to help someone breathe. May involve insertion of a hollow tube down the patient’s airway.
Asymptomatic: A person who is infected but has no symptoms of disease
Presymptomatic: A person who is infected and has no symptoms but who will develop symptoms later.
Article: How does Coronavirus kill? Clinicians trace a ferocious rampage through the body, from brain to toes https://www.sciencemag.org/news/2020/04/how-does-coronavirus-kill-clinicians-trace-ferocious-rampage-through-body-brain-toes
1. Zhu J, Ji P, Pang J, Zhong Z, Li H, He C, Zhang J, Zhao C. Clinical characteristics of 3,062 COVID‐19 patients: a meta‐analysis. Journal of Medical Virology. 2020 Apr 15. https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmv.25884
2. World Health Organization, World Health Organization. Report of the WHO-China joint mission on coronavirus disease 2019 (covid-19).
3.Klopfenstein T, Toko L, Royer PY, Lepiller Q, Gendrin V, Zayet S. Features of anosmia in COVID-19. Medecine et Maladies Infectieuses. 2020 Apr 17.
4.The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19) — China, 2020. https://cdn.onb.it/2020/03/COVID-19.pdf.pdf
5. Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the NewYork City Area. https://jamanetwork.com/journals/jama/fullarticle/2765184?utm_campaign=articlePDF%26utm_medium%3darticlePDFlink%26utm_source%3darticlePDF%26utm_content%3djama.2020.6775