AHPPC is aware of:
- very recent cases of novel coronavirus who are asymptomatic or minimally symptomatic, and
- reports of one case of probable transmission from a pre-symptomatic case to other people, two days prior to the onset of symptoms.
These data are very limited and preliminary and AHPPC still believes that most infections are transmitted by people with symptomatic disease. However, AHPPC believes that we should take a highly precautionary approach and is making the following new recommendations:
- People who have been in contact with any confirmed novel coronavirus cases must be isolated in their home for 14 days following exposure;
- Returned travellers who have been in Hubei Province of China must be isolated in their home for 14 days after leaving Hubei Province, other than for seeking individual medical care.
Given the lower number of cases in China reported outside of Hubei province, we do not currently recommend self-isolation for travellers from other parts of China or other countries. We are closely monitoring the development of cases outside of Hubei province and will update this advice if necessary.
AHPPC recognises that the evidence for pre-symptomatic transmission is currently limited, and this policy is highly precautionary. At this time, the aim of this policy is containment of novel coronavirus and the prevention of person to person transmission within Australia.
Further details of the extent of pre-symptomatic transmission is being monitored, and may result in changes to policy.
Summary of evidence to support the revised advice
New international evidence suggest that asymptomatic or minimally symptomatic infection can occur, and that pre-symptomatic transmission has occurred in at least one case cluster.
German case cluster: It has been reported that participants at a workshop in Munich had contact with a woman on 21 January. This woman, who had been in Wuhan, became symptomatic on 23 January and diagnosed following return to China. Four workshop attendees, with no travel history to China, have been confirmed with nCoV and several more are under investigation.
- A 10 year old child reported in a case series was noted as having no fever; although it is likely that this case may have had a cough sufficient to produce PCR positive sputum.
- A Japanese person reported as a case was a bus driver who transported Chinese passengers from Wuhan. The Japanese person had no history of travel outside Japan. None of the passengers were known cases.
- Several Chinese language media reports have detailed transmission from pre-symptomatic cases, but no confirmatory evidence has been published.
- WHO Sitrep (#8) states that 3 of 58 cases diagnosed outside China were asymptomatic.