ជំងឺកូរ៉ូណាវីរុស២០១៩: Prognosis

Prognosis

The severity of COVID‑19 varies. The disease may take a mild course with few or no symptoms, resembling other common upper respiratory diseases such as the common cold. Mild cases typically recover within two weeks, while those with severe or critical diseases may take three to six weeks to recover. Among those who have died, the time from symptom onset to death has ranged from two to eight weeks.

Children make up a small proportion of reported cases, with about 1% of cases being under 10 years and 4% aged 10–19 years. They are likely to have milder symptoms and a lower chance of severe disease than adults; in those younger than 50 years the risk of death is less than 0.5%, while in those older than 70 it is more than 8%. Pregnant women may be at higher risk for severe infection with COVID-19 based on data from other similar viruses, like SARS and MERS, but data for COVID-19 is lacking. In China, children acquired infections mainly through close contact with their parents or other family members who lived in Wuhan or had traveled there.

Some studies have found that the neutrophil to lymphocyte ratio (NLR) may be helpful in early screening for severe illness.

Most of those who die of COVID‑19 have pre-existing (underlying) conditions, including hypertension, diabetes mellitus, and cardiovascular disease. The Istituto Superiore di Sanità reported that out of 8.8% of deaths where medical charts were available for review, 97.2% of sampled patients had at least one comorbidity with the average patient having 2.7 diseases. According to the same report, the median time between the onset of symptoms and death was ten days, with five being spent hospitalised. However, patients transferred to an ICU had a median time of seven days between hospitalisation and death. In a study of early cases, the median time from exhibiting initial symptoms to death was 14 days, with a full range of six to 41 days. In a study by the National Health Commission (NHC) of China, men had a death rate of 2.8% while women had a death rate of 1.7%. Histopathological examinations of post-mortem lung samples show diffuse alveolar damage with cellular fibromyxoid exudates in both lungs. Viral cytopathic changes were observed in the pneumocytes. The lung picture resembled acute respiratory distress syndrome (ARDS). In 11.8% of the deaths reported by the National Health Commission of China, heart damage was noted by elevated levels of troponin or cardiac arrest. According to March data from the United States, 89% of those hospitalised had preexisting conditions.

The availability of medical resources and the socioeconomics of a region may also affect mortality. Estimates of the mortality from the condition vary because of those regional differences, but also because of methodological difficulties. The under-counting of mild cases can cause the mortality rate to be overestimated. However, the fact that deaths are the result of cases contracted in the past can mean the current mortality rate is underestimated. Smokers were 1.4 times more likely to have severe symptoms of COVID‑19 and approximately 2.4 times more likely to require intensive care or die compared to non-smokers.

Concerns have been raised about long-term sequelae of the disease. The Hong Kong Hospital Authority found a drop of 20% to 30% in lung capacity in some people who recovered from the disease, and lung scans suggested organ damage. This may also lead to post-intensive care syndrome following recovery.

+Case fatality rates (%) by age and country or US stateAge0–910–1920–2930–3940–4950–5960–6970–7980-8990+ Canada as of 5 Maycolspan="2" colspan="2" colspan="2" colspan="2" colspan="2" China as of 11 Februarycolspan="2" Denmark as of 5 Maycolspan="6" Germany as of 5 Mayhttps://www.rki.de/DE/Content/InfAZ/N/Neuartiges_Coronavirus/Situationsberichte/2020-05-05-de.pdfcolspan="6" colspan="2" colspan="2" Israel as of 3 MayItaly as of 28 AprilKY state as of 5 Maycolspan="2" MA state as of 5 Maycolspan="2" Netherlands as of 25 AprilNorway as of 5 Mayhttps://www.fhi.no/contentassets/ca5914bd0aa14e15a17f8a7d48fa306a/2020_05_05_dagsrapport-norge-covid-19.pdfPortugal as of 5 Maycolspan="2" South Korea as of 30 Aprilcolspan="2" Spain as of 5 MaySweden as of 5 MaySwitzerland as of 5 Maycolspan="2" WA state as of 3 Maycolspan="2" colspan="2" colspan="2" colspan="2" colspan="2" 
+Case fatality rates (%) by age in the United StatesAge0–1920–4445–5455–6465–7475–8485+United States as of 16 March0.00.1–0.20.5–0.81.4–2.62.7–4.94.3–10.510.4–27.3Note: The lower bound includes all cases. The upper bound excludes cases that were missing data.

+Estimate of infection fatality rates and probability of severe disease course (%) by age based on cases from China0–910–1920–2930–3940–4950–5960–6970–7980+Severe disease(0.0–0.0)(0.02–0.08)(0.62–2.1)(2.0–7.0)(2.5–8.7)(4.9–17)(7.0–24)(9.9–34)(11–38)Death(0.00016–0.025)(0.0015–0.050)(0.014–0.092)(0.041–0.19)(0.076–0.32)(0.34–1.3)(1.1–3.9)(2.5–8.4)(3.8–13) Total infection fatality rate is estimated to be 0.66% (0.39–1.3). Infection fatality rate is fatality per all infected individuals, regardless of whether they were diagnosed or had any symptoms. Numbers in parentheses are 95% credible intervals for the estimates.

ភាពស៊ាំ

It is unknown (as of April 2020) if past infection provides effective and long-term immunity in people who recover from the disease. Some of the infected have been reported to develop protective antibodies, so acquired immunity is presumed likely, based on the behaviour of other coronaviruses. However, cases in which recovery from COVID‑19 was followed by positive tests for coronavirus at a later date have been reported. These cases are believed to be lingering infection rather than reinfection, or false positives due to remaining RNA fragments. Some other coronaviruses circulating in people are capable of reinfection after roughly a year.