I’m just wondering if anyone has seen any more up to date information on: 1. People who might carry COVID and pass it on without symptoms themselves? I know some can be infectious just before showing symptoms, but I’m wondering about the ability to be a longer term spreader of COVID without the symptoms appearing shortly afterwards? 2. People who have had COVID? Does this mean they no longer pass COVID onwards? I wonder too does the ability to transmit COVID differ between: a) People who have recently had COVID and fully recovered? b) People who have had COVID some time ago and fully recovered? c) People who have ongoing Long COVID problems after an infection some time ago? Thoughts? I am likely to have some contact in the coming days with an individual fitting 2c. I anticipate taking a number of precautions, but I’m interested to know if there is any data on what the risks might be?
My understanding is as follows, but I am hopeless at remembering sources, so it would be interesting what other people say: 1. Can people who are totally asymptomatic pass on Covid-19? Yes, it is possible to have and spread the virus without ever developing any symptoms. I read something relatively recently that this particularly is relevant to spreading the virus by children, who can have higher levels of the virus than adults but remain asymptomatic. 2. Are people who have had the virus then safe? a. Recently recovered - I am assuming that people who have relatively recently recovered are not a source of the virus themselves, but in theory they could be passive carriers if exposed in the same way as an inanimate object or with a pet* that goes from one person to the next for attention. Presumably this is pretty low risk as long as hygiene is observed. b. Recovered some time ago - I assume this is still an area of uncertainty, though examples of people that have had the virus more than once are still fairly rare. It is still not known how long acquired immunity persists, whether it is months or a year or longer. Presumably it is a matter of balancing risks. (I think I read a suggestion that people getting reinfected are likely to have more severe symptoms, so perhaps are less likely to be totally asymptomatic.) Does any one know of any more recent studies on how long acquired immunity typically lasts? c. On-going Covid symptoms - presumably those people with severe active ongoing infections are still potentially spreading the virus, but in general these people are mostly still in hospital, as their health is such that they are unable to fight off the virus. Further some of the people that are candidates for a second infection, may have rather had a reactivation of the virus lurking within their body. However presumably they are less likely or even unlikely to be a source of infection while the virus is ‘dormant’. Presumably when you get to over three to six month period long-Covid is no longer based on any measurable ongoing viral infection, as with the other post viral conditions and ME, so such people would not be a primary source of the virus. My understanding of the current UK guidelines is that even if some one is previously recovered from the virus, if exposed to someone else with the virus they should self isolate for two weeks. But I recently scored much lower than expected on a quiz about the then UK guidelines I am not confident about that. *Note - initial advice that pets could not be a primary source of the virus, just occasional passive carriers on the fur may have been premature. I read that so far two cats in the UK have been found to have the virus, though there may now be more up to date information, also there was the case of the fur farm where a majority of the mink housed there had the virus. [added - Covid-19 has been a problem in farmed mink in Spain, the Netherlands and the USA, see https://www.sciencemag.org/news/2020/08/covid-19-hits-us-mink-farms-after-ripping-through-europe )
Thanks for this response @Peter Trewhitt - I must go and look up about the mink farm! Re Long COVID - Do you know are the symptoms seen as ongoing COVID symptoms, or are they other symptoms that are more ME like? I had the notion that Long-COVID patients had recovered from COVID but were left with post-COVID symptoms that were no longer regarded as strictly COVID.... hmmmm. The individual I mentioned had COVID right at the start of all this. I think it was early March.
I was trying to distinguish between those with an ongoing acute active infection at several weeks who are likely to be more severely ill, and long Covid at several months where presumably there is no demonstrable active infection, the former being a potential source of the virus, but the latter not. However in practice I don’t know how easy it would be to distinguish the two, or if there is any clear evidence for this assumption. I am expecting soon a visit from my god daughter and her mother both of whom had the virus in April, but am ‘gambling’ on them still being safe as we are not yet seeing any significant numbers of reinfections here in the UK.
I think the answer is nobody knows. It seems the most infectious stage is in the first few days when there are symptoms such as cough and breathlessness, but there have been instances of people testing positive well after that phase. If it were me I would act with caution, keep to the 2 metre rule, if indoors wear masks and keep windows open, avoid touching surfaces, wash hands, avoid touching your face etc. just as I would for someone who hadn't had covid yet as far as they know.
Yes @Peter Trewhitt I too think some-one who had the virus a while ago (whether with Post-COVID symptoms, or totally well again) is “likely” to be no more of a risk than some-one who has never had COVID. Possibly less of a risk, but who knows!
There's just been a report on the BBC News that someone has got the virus twice. I think it was a slightly different version, and in a different country. Can't remember if it was the usual news or the World Service. Here's a report on it: https://www.dailymail.co.uk/news/ar...year-old-man-Hong-Kong-person-reinfected.html
It is just as you would expect. He had the virus and recovered then he came in contact with another strain which colonised his body but his immune system prevented him from becoming ill again. It is the sort of thing that must happen to us all the time. He wasn't ill it was just picked up in a test done for other reasons. Thinking about how likely we are to get the virus from someone who had it a while ago. In all infections, viral particles have to leave someone to pass it on. To do that they have to be carried out of one body and picked up by another so you can have blood borne infections or faecal - oral routes. Respiratory viruses are passed in droplets when we breathe out or talk so the virus has to be in the mouth, trachea or lungs. In long covid the immune system has either got rid of the virus or the virus is still present but evading the immune system so it is not likely to be where it can be breathed out. Coronavirus infections are common and people stop being infectious when they recover and there is no evidence that SARS-CoV-2 is any different so logically I doubt if there is much risk beyond the risk of anyone visiting who may have pick up virus particles on their hands on the way there.
Here is a report of someone having a second bout of Covid-19 that was asymptomatic the second time round. https://www.sciencemag.org/news/202...-ojzo97Fx6qr5Pr_JwVMl6ydRxrll6DHwxyje0aOc8JIo This suggests that to be absolutely safe you have to treat everyone the same, whether they have previously had the virus or not.
