echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Biochemistry News > Biotechnology News > Nature: There is plenty of evidence that asymptomatic infections or cause coVID-19 pandemics.

    Nature: There is plenty of evidence that asymptomatic infections or cause coVID-19 pandemics.

    • Last Update: 2020-08-04
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com
    Original title: Nature: There is plenty of evidence that asymptomatic infections or the prevalence of COVID-19 Source: Biovalley scientists are anxious to estimate the proportion of people with mild symptoms or asymptomatic who may spread pathogens.
    With the global outbreak of coronaviruses, the team is working to solve an important epidemiological problem -- how many cases of infected people have mild or no symptoms and may transmit the virus to others.
    preliminary detailed estimates of these hidden cases suggest that they may account for about 60 per cent of all infections.
    many scientists suspect that there is an undiscovered pool of hidden cases that shows limited symptoms or asymptomatic, as more and more infected people cannot be linked to known CASES of COVID-19 or affected areas.
    most people with mild infections are not well enough to seek medical attention and are likely to miss screening methods such as temperature tests, the severity of the phenomenon and its role in the spread of the virus remain elusive. "Understanding the proportion of asymptomatic or mild cases is important to us to understand what is causing this particular epidemic," said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota
    .
    "This is different from those who try to understand the number of unreported cases -- those that are missed because the authorities are not doing enough tests, or "preclinical cases" that have been infected with the virus but have not shown symptoms.
    to assess the extent of the hidden infection, a team of researchers in China and the United States developed a model that used clinical data on 26,000 laboratory-confirmed cases received by the Wuhan Municipal Health Board in Hubei Province, China.
    undiscovered cases were published online on March 6 in a preprint, and the group noted that as of February 18, a large number of people in Wuhan had contracted COVID-19, but no diagnosis had been diagnosed.
    , most of these unreported cases occur in people with mild or unasymptomatic symptoms who are still contagious, according to the co-authors. "According to our most conservative estimates, at least 59 percent of those infected are untested and may be infected," said Wu Tangchun, a public health expert at Huazhong University of Science and Technology in Wuhan, who led the study.

    " this may explain why the virus spreads so fast around the world. Adam Kucharski, a disease modelling expert at the London School of Hygiene and Tropical Medicine, said the team's findings were consistent with several other estimates based on much smaller data sets.
    "This is the latest analysis of the best data set we have," he said, and the method was reasonable.

    but the model assumes that everyone in the community has the same opportunity to reach out to anyone else.
    in reality, "you have more opportunities to interact with a small group of people: your family, friends, and colleagues," says Gerardo Cowell, a mathematical epidemiologist at Georgia State University in Atlanta.
    , he says, the model may overestimate transmission rates by assuming uniform contact, overestimating the number of infections with mild or asymptomatic symptoms.
    , but he said the results were broadly correct.
    more and more evidence, another study surveyed 565 Japanese citizens who were repeatedly tested and monitored for the virus and symptoms.
    in a paper published March 13 in the Journal of International Journal of Infectious Diseases, a Japanese research team reported that 13 evacuees were infected, 31 percent (4 of them) without symptoms.
    , however, Cowell said the best evidence of asymptomatic cases may come from the Diamond Princess, which had an OUTBREAK of COVID-19 off the coast of Japan in early February.
    the ship was quarantined and 3,711 passengers and crew were repeatedly tested and closely monitored.
    Modelling study by Cowell, published March 12 in the journal Eurovision, showed that about 18 percent of the roughly 700 infected people on the Diamond Princess never developed symptoms. "you have to remember that this is a special group," Says Cowell,
    .
    older people tend to underperform after contracting the new coronavirus, he suspects the asymptomatic infection rate in the general population may be closer to the 31 percent reported by the Japanese team.
    taking into account the results of several studies, Cowell believes that asymptomatic or mild cases add up to about 40-50 percent of all infections.
    the virus falls off, but do people with mild or asymptomatic symptoms infect others? In a preprinted study published on March 8, a German team showed that some PATIENTs with COVID-19 had higher levels of the virus in the throat swab when their early symptoms were mild.
    researchers say this means pathogens can easily be released by coughing or sneezing, a process known as virus shedding and spreading to others.
    another research team in China found high viral loads in 17 patients with COVID-19 shortly after the onset of the disease.
    in addition, researchers recently reported in The New England Journal of Medicine that another infected person had never developed symptoms, but that the amount of the virus released was comparable to that of the person who developed the symptoms.
    Osterholm says this is the first detailed analysis of how well the virus has fallen off at different stages of the disease.
    , he said, the data confirmed many scientists' guesses that some infected people are "highly contagious when symptoms are mild or asymptomatic."
    but stressed that the problem was still unclear.
    many scientists worry that this could also lead to an underestimation of children's susceptibility to the virus.
    a study of more than 700 infected children in China found that 56 percent had mild or no symptoms.
    researchers say that if these findings are not a problem, urgent measures are needed to contain mild and asymptomatic cases that are exacerbating the influenza pandemic.
    they called for schools to be closed, public meetings to be cancelled and people to stay at home and stay away from public places.
    "Strong social alienation measures are the only way to stop the spread of the virus," Cowell said.
    (Bioon.com):【1】Covert coronavirus infections could be seeding new outbreaks【2】Wang,C.et al. Evolving Profiley and Impact of Non-Pharmaceutical Interventions on the Outbreak of Coronavirus Disease 2019 in Wuhan, China.Preprint at medRxiv https://doi.org/10.1101/2020.03.20030593 (2020). The Bigford of the asymptomatic ratio of novel coronavirus infections (COVID-19), Int.J.Infect.Dis.https://doi.org/10.1016/j.ijid.2020.03.020.4 Mizumoto, K., Kagaya, K. salebski, A. and Chowell, G. Estimating the asymptomatic of coronavirus disease 2019 (COVID-19) case board board the the scruise diamond Princess Ship, Yokohama, Japan, 2020.Euro. Surveill.25, 2000180 (2020). (5) Woelfel, R.et al. Sienand and viroso assessment of the case of coronavirus disease 2019 in a travel-associated transmission cluster. Preprint at medRxiv https://doi.org/10.1101/2020.03.05.20030502 (2020). SARS-CoV-2 Viral Load in Upper HavenS of Infected Patients.N.Engl.J.Med.382, 1177-1179 (2020). DOI: 10.1056/NEJMc2001737 (7) Dong, Y.et al. Profile S of 2143 Pediatric Patients With 2019 Coronavirus Disease in China.Pediatrics https://doi.org/10.1542/peds.2020-0702 (2020).
    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.