Maria Van Kerkhove said during a press briefing Monday that the spread of COVID-19 by people who have the coronavirus but are not showing symptoms was rare. Many countries, including the United States, adopted lockdown strategies because they recognised that isolating only people who were sick might not be enough to contain the epidemic.
Dr. Maria Van Kerkhove, head of the WHO's emerging diseases and zoonosis unit, said on Tuesday that asymptomatic spread is a "really complex question" and much is still unknown. Sometimes the word is used to describe people who have not started to show symptoms but who eventually will, in which case we should call them presymptomatic - and research has shown that they can actually be contagious before you start to feel bad.
Following an onslaught of confusion expressed from social media, including from doctors, journalists, and epidemiologists, the World Health Organization hosted a livestream on Facebook, Twitter, and LinkedIn, to clarify questions surrounding transmission of the CCP virus, commonly known as the novel coronavirus. "I wasn't stating a policy of World Health Organization or anything like that", she said.
Looking at investigations of clusters of infections from various countries, she said that where an asymptomatic case had been followed up it was "very rare" to find secondary infections among their contacts.
She said: "Some estimates of around 40 percent of transmission may be due to asymptomatic (cases), but those are from models". The US leads the world in Covid-19 infections, with almost two million cases, according to Johns Hopkins, while Brazil is second, with over 707,000 as of Tuesday. "The best scientific studies to date suggest that up to half of cases became infected from asymptomatic or pre-symptomatic people". One of the complications is that some people who appear to be infected but asymptomatic are in fact pre-symptomatic - they can go on to, for instance, experience a mild course of disease.
People with symptoms like sneezing and coughing have a high viral load in their body, which imposes a high chance of infecting other people.
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Not easy to do, considering that Dr. Van Kerkhove had been clear about what she was saying and she's rather knowledgeable about this pandemic.
Lawrence Gostin, director of the O'Neill Institute for National and Global Health Law at Georgetown University, tells BuzzFeed News, "WHO is tarnishing its reputation as a science agency by putting out conflicting and confusing statements". And asymptomatic patients often fly under the radar, coming to be identified only through heavy population testing or when they're in the same household as ill patients.
"As part of a comprehensive approach, digital contact-tracing tools offer the opportunity to trace larger numbers of contacts in a shorter period, and to provide a real-time picture of the spread of the virus", Dr. Tedros said.
That, the WHO's Mike Ryan said today, is why COVID-19 has spread so widely around the globe. Oh yeah, that's right, to prevent the spread of the disease by asymptomatic carriers.
In Southeast Asian countries, where to a great extent transmissions have been under control, governments are more concerned about the re-emergence of clusters, while in South America, the issue of PPE for health workers has not gone away, said Ryan.