Last week (June 11) in the first of a three part series on the coronavirus crisis Dr Andrew Bamji set out the history of the event to date, and this week and next week he answers some of the most frequently asked questions.
Can you get SARS-CoV-2 without symptoms?
Yes. That means that you might be able to spread it because you didn’t know you had it.
How do you catch it?
From someone else’s cough droplets. That’s why masks are a sensible idea; you can’t cough over someone else, and if they cough over you, you have some protection. However, a contact tracing exercise in Singapore showed that a church congregation picked it up directly from an infected couple (who didn’t know they were infected) but also that the couple who sat in the same seats for a later service also acquired it. This shows that the virus can hang about on surfaces for a while. That’s why handwashing is important too. And gloves.
What symptoms does SARS-CoV-2 cause?
Dry cough, fever and loss of smell (anosmia) are important ones. You won’t know that your blood oxygen levels are falling due to lung involvement until very late, because (unusually for this problem) it doesn’t make you breathless to begin with. However a low blood oxygen is highly important in terms of seeking medical advice. The blood oxygen level can be measured with a simple and inexpensive device called a pulse oximeter. Every surgery and care home should have one or more; you can get your own on the internet.
How do you test for Covid-19?
If you think you might have the illness acutely, you get a test showing you have active infection. This is the antigen test. However, there are false negatives, so it is not entirely reliable. If you think you have had it already and recovered, an antibody test may prove this, but again a negative test is inconclusive. This is why social distancing measures are important; whether you have it or not, you won’t spread it if you are far enough apart.
Why are some groups more likely to die than others?
As yet we don’t know. The elderly are at high risk, as are the obese, those with diabetes or underlying lung or heart disease, and some ethnic groups are at high risk too. This may be a combination of changes in the immune system as one ages or from hormonal effects, or genetic differences that allow the virus to infect cells more easily. It’s also possible that close social interactions (for example, within large family groups or religious services) may play a part in worsening transmission, but probably doesn’t explain the higher death rate.
The BAME issue has become a hot potato, but a breakdown of risk indicates that the highest risk is in people from Bangladesh and Pakistan, but not India. The risk in people of African origin is high, but not as high as the Bangladeshi group. We don’t know enough yet to understand all of this. It may take years of analysis.
Can children get sick from SARS-CoV-2?
Yes, but it’s very rare. It causes a condition similar to one seen in paediatric rheumatology clinics, called Kawasaki disease, which is due to blood vessel inflammation (vasculitis) which is treatable. It also appears that children do not transmit SARS-CoV-2. Why not? We don’t know yet.
What actually happens in Covid-19 disease?
The virus latches onto a cell receptor called ACE-2. These receptors are found widely in many surface cells, or epithelial cells. The virus then gets into these cells, and makes them leak, rather like popping a water-filled balloon. The cells lose fluid and cannot function properly. In the nose the smell receptors go. In the lungs fluid leaks into the air spaces. The body’s immune system then goes into overdrive and releases large amounts of inflammatory chemicals, called cytokines, setting off a chain reaction throughout the body which results in abnormal blood clotting, heart muscle damage, gut leakage and kidney failure.
Why do so many people who go onto ventilators die?
The lung damage caused by the virus and the cytokine storm means the lung lining cells cannot transfer oxygen to the blood; also the red blood cells cannot pick it up, because they too are damaged. Forcing more oxygen in, when a patient is very severely affected, simply does not work. Patients bad enough to need ventilation in an ICU are the very sickest; even without having Covid-19, the mortality in ventilated ICU patients is high.
So why was there this rush to have more ventilators?
We didn’t understand what was happening in the lungs. It’s different from most infections and blood clots, but initially it was thought to be similar. And better safe than sorry. On the positive side it shows what can be done quickly in a crisis.
Next week Andrew continues to answer your questions and may have some up to date comments on where we have now got to with the crisis.
Image Credits: Colleen Lennon .
Thanks for your report.
It’s very informative.
Thanks for the second instalment. Most interesting. Rother District has the second highest number of elderly in its population , 23%, after North Norfolk, and the last time I looked , Rother was 156th in the league table for number of Covid cases.My question is, why have we had so few cases comparitively?
Is it that our air is less polluted? Do we absorb more Vitamin E than town-dwellers and gain more protection?
Or are there more questions to be answered?
Gosh, Norman, there are vast numbers of unanswered questions still! But Rother has less cases because there are no major centres of population for it to spread within, and the epicentres of the big cities locked down before weekenders could bring it down to the coast. It requires pretty close contact to transmit, and rush hour in Rye is not quite like London, where public transport is packed solid. It’s possible that the outdoor life of us rural people helps by keeping our Vitamin D levels up, and sunlight kills the virus more quickly, but I don’t think air pollution has anything to do with it,
I am sure when it’s all over that the post-mortem will make lots of things much clearer. I hope to keep updating Rye News when it seems important to do so, but meanwhile I am blogging regularly.
Totally agreed with your latest update Andrew . Where would this stop with statues , plaques etc many countries and in our case many counties would have problems . We cannot remove our history and should not but , rather recognise the past and the ideas repugnant to us as they are today but sadly were acceptable then .
All lives matter , not just one sector .
To promote a single element could fire so many emotions and cause disruption and even anarchy amongst our democratic society which is so concerning .
Rosemary Williams
I don’t see how this post is relevant to the article, but more importantly, it is a veiled attack on the Black Lives Matter campaign. I do take issue with Andrew Bamji’s statement that ‘We don’t know enough yet to understand all of this [the BAME issue]. It may take years of analysis.’ Actually we do know why: it is due to wealth and social inequality.
If Rye News wants to encourage that debate, it might be better to write a dedicated article to that effect. In the meantime, I can recommend listening to this clip: https://www.bbc.co.uk/programmes/p08ht5t4
Actually, Dominic, we do not know why. Researchers have already shown that susceptibility to severe Covid-19 may be partly a function of age, obesity, diabetes and blood group. There are scientific explanations for all these risk factors. Blood group A has a higher prevalence in non-white people as it happens and that is the group showing the highest risk. Vitamin D levels may be important – not proven. Social crowding may influence acquisition of the virus, as might increased exposure (hence hospital workers, bus driver etc) but there is no obvious reason why the Covid-19 syndrome is so severe on those grounds. The current theory is that some or all of these factors may change the ACE-2 receptors on cell surfaces in a way that makes the coronavirus more easily able to penetrate cells. That’s genetic, not environmental. Ponder also the fact that, of hospital consultants who have died in the UK, a large number have been of Asian and in particular Bangladeshi origin. Hospital consultants are neither poor nor socially unequal; as an ex-consultant, I have worked with many and know how much they earn.
I will grind no BLM axe, not least because I am from an ethnic minority myself, at least in part but the clip you suggested we listen to has no medical or scientific backing whatever for the conclusion drawn (by a journalist, not a scientist) that wealth and social inequality are responsible for Covid-19 deaths in the BAME community. A can cause C. B can cause C. That does not mean that B causes C. There is a difference between causation and association.
Social inequality may play some part; I have an open mind, and certainly in the third world the means to stop deaths may be lacking. But this is not a simple issue; when one is trying to determine causation and risk, it is necessary to correct for all risk factors, which requires huge surveys, masses of data, population stratification and so on. So I stick with my contention that scientific analysis will take time.