| No images? Click here Friday 24 April 2020 "Immunity passports" in the context of COVID-19Scientific Briefhttps://www.who.int/news-room/commentaries/detail/immunity-passports-in-the-context-of-covid-19 WHO has published guidance on adjusting public health and social measures for the next phase of the COVID-19 response.(1) Some governments have suggested that the detection of antibodies to the SARS-CoV-2, the virus that causes COVID-19, could serve as the basis for an “immunity passport” or “risk-free certificate” that would enable individuals to travel or to return to work assuming that they are protected against re-infection. There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection. The measurement of antibodies specific to COVID-19 The development of immunity to a pathogen through natural infection is a multi-step process that typically takes place over 1-2 weeks. The body responds to a viral infection immediately with a non-specific innate response in which macrophages, neutrophils, and dendritic cells slow the progress of virus and may even prevent it from causing symptoms. This non-specific response is followed by an adaptive response where the body makes antibodies that specifically bind to the virus. These antibodies are proteins called immunoglobulins. The body also makes T-cells that recognize and eliminate other cells infected with the virus. This is called cellular immunity. This combined adaptive response may clear the virus from the body, and if the response is strong enough, may prevent progression to severe illness or re-infection by the same virus. This process is often measured by the presence of antibodies in blood. WHO continues to review the evidence on antibody responses to SARS-CoV-2 infection.(2-17) Most of these studies show that people who have recovered from infection have antibodies to the virus. However, some of these people have very low levels of neutralizing antibodies in their blood,4 suggesting that cellular immunity may also be critical for recovery. As of 24 April 2020, no study has evaluated whether the presence of antibodies to SARS-CoV-2 confers immunity to subsequent infection by this virus in humans. Laboratory tests that detect antibodies to SARS-CoV-2 in people, including rapid immunodiagnostic tests, need further validation to determine their accuracy and reliability. Inaccurate immunodiagnostic tests may falsely categorize people in two ways. The first is that they may falsely label people who have been infected as negative, and the second is that people who have not been infected are falsely labelled as positive. Both errors have serious consequences and will affect control efforts. These tests also need to accurately distinguish between past infections from SARS-CoV-2 and those caused by the known set of six human coronaviruses. Four of these viruses cause the common cold and circulate widely. The remaining two are the viruses that cause Middle East Respiratory Syndrome and Severe Acute Respiratory Syndrome. People infected by any one of these viruses may produce antibodies that cross-react with antibodies produced in response to infection with SARS-CoV-2. Many countries are now testing for SARS-CoV-2 antibodies at the population level or in specific groups, such as health workers, close contacts of known cases, or within households.(21) WHO supports these studies, as they are critical for understanding the extent of – and risk factors associated with – infection. These studies will provide data on the percentage of people with detectable COVID-19 antibodies, but most are not designed to determine whether those people are immune to secondary infections. Other considerations At this point in the pandemic, there is not enough evidence about the effectiveness of antibody-mediated immunity to guarantee the accuracy of an “immunity passport” or “risk-free certificate.” People who assume that they are immune to a second infection because they have received a positive test result may ignore public health advice. The use of such certificates may therefore increase the risks of continued transmission. As new evidence becomes available, WHO will update this scientific brief. References
WHO continues to monitor the situation closely for any changes that may affect this interim guidance. Should any factors change, WHO will issue an update. Otherwise, this scientific brief will expire 1 year after the date of publication.
 You are receiving this NO-REPLY email because you are included on a WHO mail list.  |
Mohon diloloskan Bp Ibu Moderator. 🙏 Acara ini sangat bagus. Peserta webinar akan mendapatkan *perlindungan asuransi bebas premi bagi peserta webinar* dan *raih hadiah isi ulang OVO @50,000 untuk 3 penanya terpilih*. Dear Bapak Ibu HRD, *PT. Prudential Indonesia mengadakan HR Gathering PRUWorks 19 November 2020 !* Jangan lewatkan _talkshow_ interaktif mengenai *Redefining Workforce In The Era Of Disruption*. Langsung via *Zoom Webinar* bersama pembicara yang sangat kompeten dibidangnya. 🎤Speaker : Prof Rhenald Kasali Ph.d 🎤 Speaker : Isdar Marwan 🗣 Opening : Nick Holder 🎥 Moderator: Lili Yunita 📽 MC : Ruth Elizabeth tanggal dan waktunya : *Kamis, 19 November 2020 pukul 10.00 WIB*. Oleh sebab itu, Bapak Ibu terundang untuk mengikuti acara tersebut. Bapak Ibu silahkan melakukan pendaftaran melalui link : https://bit.ly/pruworkshr19 untuk mendapatkan * Zoom Meeting ID dan Passwo
Comments
Post a Comment