Coronavirus Disease 2019 (COVID-19) Tổng quan về bệnh

Cập nhật: 28 November 2024

Nội dung của trang này:

Nội dung của trang này:

Giới thiệu

Coronavirus disease 2019 (COVID-19) is a respiratory tract infection caused by a newly emergent coronavirus, SARS-CoV-2, first reported in Wuhan, China in December 2019.

Dịch tễ học

MP 7 Oct - Vietnam
Tính đến ngày 11 tháng 2 năm 2024, trên toàn cầu Ä‘ã có 774.631.444 ca mắc COVID-19 được xác nhận, bao gồm 7.031.216 ca tá»­ vong, được báo cáo cho Tổ chức Y tế Thế giá»›i (WHO). Theo từng khu vá»±c, các ca bệnh được xác nhận dá»±a trên dữ liệu của WHO tính đến ngày 11 tháng 2 năm 2024 nhÆ° sau:

Nguyên nhân

SARS-CoV-2 is classified within the genus Betacoronavirus (subgenus Sarbecovirus) of the family Coronaviridae. It is an enveloped, positive-sense, single-stranded ribonucleic acid (RNA) virus with a 30-kb genome. SARS-CoV-2 is most genetically similar to SARS-CoV-1 and both belong to the subgenus Sarbecovirus within the genus Betacoronavirus; however, SARS-CoV-1 is currently not known to circulate in the human population. 

A variant of concern is a SARS-CoV-2 variant with genetic changes that are predicted or known to affect virus characteristics such as transmissibility, virulence, antibody evasion, susceptibility to therapeutics, and detectability. It is also identified to have a growth advantage over other circulating variants in more than one WHO region with increasing relative prevalence alongside an increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health. As of 18 May 2023, there is no variant of concern. Variant of concern would also need to meet one of the following criteria: 

  • Detrimental change in clinical disease severity
  • Change in COVID-19 epidemiology causing a substantial impact on the ability of health systems to provide care to patients with COVID-19 or other illnesses thus requiring major public health interventions
  • Significant decrease in the effectiveness of available vaccines in protecting against severe disease 

A variant of interest is a SARS-CoV-2 variant with genetic changes that are predicted or known to affect virus characteristics such as transmissibility, virulence, antibody evasion, susceptibility to therapeutics, and detectability. It is also identified to have a growth advantage over other circulating variants in more than one WHO region with an increasing relative prevalence alongside an increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health.

  Currently Circulating Variants of Interest as of 09 August 2023
Pango Lineage Nexstrain Clade
Genetic Features
Earliest Documented Samples
XBB 1.5 23A Recombinant of BA.2.10.1 and BA.2.75 sublineages, ie BJ1 and BM.1.1.1, with a breakpoint in S1 XBB.1 + S:F486P (similar spike genetic profile as XBB.1.9.1) 21 October 2022
XBB.1.16
23B Recombinant of BA.2.10.1 and BA.2.75 sublineages, ie BJ1 and BM.1.1.1 XBB.1 + S:E180V, S:K478R and S:F486P
09 January 2023
EG.5
Not assigned  XBB.1.9.2 + S:F456L
Includes EG.5.1: EG.5 + S:Q52H
17 February 2023

As of 15 March 2023, WHO will assign Greek letters to variants of concern while variants of interest will be referred to using established scientific nomenclature systems (ie Nexstrain and Pango). 

Sinh lý bệnh

Infection is caused by binding of the viral surface spike protein to the human angiotensin-converting enzyme 2 (ACE2) receptor after activation of the spike protein by transmembrane protease serine 2.

Mode of Transmission

The mode of transmission of COVID-19 is by contact and droplet transmission through direct, indirect, or close contact with infected individuals through secretions (ie saliva and respiratory secretions). Airborne transmission occurs during medical procedures that generate aerosols (aerosol-generating procedures).

Fomite transmission is through contaminated surfaces and objects. Viable SARS-CoV-2 virus and/or RNA detected by reverse transcription-polymerase chain reaction (RT-PCR) can be found on those surfaces for periods ranging from hours to days, depending on the ambient environment (including temperature and humidity) and the type of surface.

Other modes of transmission include the urine, feces, plasma, or serum.

Incubation Period 

Generally, after exposure to the virus, the mean time to develop symptoms is 4 to 6 days, with a range of between 1 and 14 days. 

Yếu tố nguy cơ

Factors that Determine Transmission Risk  

Transmission risk is determined by the following factors:

  • Whether the virus is still replication-competent
  • Presence of symptoms (eg cough)
  • Behavior and environmental factors associated with the infected person
  • COVID-19 patient starts to gradually produce neutralizing antibodies that reduce the risk of virus transmission, usually 5 to 10 days after infection with SARS-CoV-2