One of the UK patients that contracted coronavirus has spoken about his experiences to the media.
Prof Sheila Bird, Formerly Programme Leader, MRC Biostatistics Unit, University of Cambridge, said:
“Most welcome is news of the recovery of the UK patient who was infected while attending a conference in Singapore and subsequently infected others, many soon after his own infection and apparently before being symptomatic. This unwitting infection-network raises two questions: whether, for some individuals at least, infectiousness may be high with novel coronavirus-19 soon after one’s own exposure; and whether the advice [Anyone experiencing symptoms, even if mild, after travelling from mainland China, Thailand, Japan, Republic of Korea, Hong Kong, Taiwan, Singapore, Malaysia or Macau, is advised to stay indoors and call the NHS 111 phone service] may now be too restrictive as only the index case had the requisite travel history – not his secondary infected.
“Commendably, the organizers of the conference in Singapore took the initiative of alerting delegates after a first, a non-UK participant, became a confirmed case. Has international collaboration been mobilized (a major challenge but informative if do-able) to arrange for the testing of other delegates so that the transmissions, including asymptomatic, might be identified in the network of the conference’s participants?”
Dr Stephen Griffin, Associate Professor at University of Leeds and Chair of the Virus Division, Microbiology Society, said:
“The issue with the term “super-spreader” is that it implies that the person in question is inherently more able to pass on disease compared with others. In fact, the term is relatively poorly defined. It must be remembered that the spread of a virus like nCoV depends upon a number of factors that ultimately comprise a “transmission event”. This will depend upon the patient and what stage of disease they are in, their behaviour, their environment, and of course time. We make a collective judgement on all of these factors when we calculate a R0, which for nCoV appears to be between 2-3, but we must remember that this calculation is based upon averages and probabilities, rather than a definitive number of transmissions – some patients will infect significantly more than this, whereas others may not pass infection on at all. For example, a patient that is very unwell, coughing without practicing good hygiene, and who is then stuck in a crowded lift for an hour is far more likely to spread infection to multiple recipients compared with someone that self-isolates at the first sign of symptoms.
“However, the so-called super spreader case may support that the virus can be shed from individuals prior to the onset of symptoms, which we are hearing more and more anecdotally, although this hasn’t been confirmed clinically. If this is the case, this would make the problem of containing spread more like controlling a flu outbreak, rather than what was experienced with SARS. The fact that such a trail of transmission arose from otherwise relatively normal travelling behaviour is a consequence of our “global village” and should illustrate the immense challenge faced by health care agencies across the globe. It is likely that transmission chains such as this may occur again in the UK, particularly as the number of countries with ongoing transmission grows. However, what then becomes critical is the rapid identification, isolation and contact-tracing undertaken by the authorities, which appears to be robust at present. When one considers the scale of this challenge in China, it becomes all the more impressive that the many thousands of cases there have only really spilled over into a handful of pockets globally – we should applaud the efforts of the Chinese people, the WHO and other agencies, including PHE, that are safeguarding against this new virus.”
Prof Brendan Wren, Professor of Microbial Pathogenesis, London School of Hygiene & Tropical Medicine (LSHTM), said:
“There is no clear evidence that individuals with the new corona virus can be “super shedders” or “super spreaders.” It is likely that individuals may have mild symptoms prior to unwittingly transferring the virus. Thus, similar to the first reported index case in Germany, the UK index case does not provide clinical evidence of asymptomatic spread of the new corona virus. In the UK PHE are dealing adequately with potentially newly infected individuals on a case by case basis”
Prof Rowland Kao, Sir Timothy O’Shea Professor of Veterinary Epidemiology and Data Science, University of Edinburgh, said:
“While possible evidence of an asymptomatic carrier is important, as important is that, if the figure of 11 infectious contacts is due to direct contact with him, rather than due in part to chains of infection, this is substantially more than one would expect to see from an average infected individual. If, for example if the average person infected 4 individuals (and this would be a high estimate for this coronavirus), then there is a less than 1% chance of a single average individual infecting 11. They are already calling him a ‘super-spreader’. What isn’t known is why – it could for example because he produces more virus, or it could be because his behaviour and activity resulted in more potential cases. If there are others like him, understanding why is going to be crucial to gaining the upper hand on the epidemic.”
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