COVID-19 Where Will This Take Us?
by Sarah Ann Macklin
WHERE ARE WE HEADING?
Vivienne Parry OBE, head of Engagement at Genomics England explains the science.
I aim to bring my readers evidence based facts from experts who are trusted and reliable sources. Vivienne Parry explains below the facts about the virus, the evidence which we know so far and where we are heading in terms of immunisation and a possible vaccine. As we are all frightened during this time of a global pandemic, one which has never been seen on this scale in our lifetimes before, it’s important we share reliable and evidence based sources of knowledge.
COVID-19 EXPLAINED
COVID-19 is a disease with pneumonia like symptom caused by the Severe Acute Respiratory Syndrome virus (SARS CoV-2). It was first seen in Wuhan, China in December 2019.
SARS CoV-2 is a coronavirus. Seven are known to infect humans, four that cause mild cold like symptoms and three more serious ones, SARS (Severe Acute Respiratory Disease Syndrome), MERS (Middle Eastern Respiratory Syndrome) and now SARS CoV-2.
It’s a zoonosis – a virus very similar to those seen in animals (bats, pangolins and civets) – which has been transmitted to man, probably in the wet markets of Wuhan, and then become transmissible between humans. Compared to other viruses, SARS CoV-2 is more contagious than flu or hepatitis but much less contagious than say mumps or measles. The reason it appears so infectious is that no humans have any immunity to this.
RNA VS A DNA VIRUS, WHAT IS COVID-19 AND WHAT IS THE DIFFERENCE?
Coronaviruses are spherical and covered in what looks like a crown of thorns or spikes, hence their name. They are enveloped RNA viruses, that is their genome – their instruction manual – is not made of DNA like humans (or indeed some other viruses) but of a single short strand of RNA, which is closely related to DNA and is enclosed in a fatty membrane which helps hide it from the host’s immune system.
The virus replicates every 30 minutes and every time it replicates, there are likely to be small changes in its genome. Viruses must change constantly in order to outwit both host immune systems and medications. If any change occurs amongst members of a population of the same virus, which gives some of them advantage in either replication, infection or disguise, that version of the virus will prosper whereas those that don’t have this advantage will perish. The virus with the advantageous change then becomes dominant and is the version passed on.
ARE THERE DIFFERENT STRAINS OF COVID-19?
At the moment there are two strains of SARS C0V-2 but one is not more harmful than the other. Frequently, viruses that spread very widely become less, rather than more harmful as they do so.
WHAT ARE THE SYMPTOMS? WHY ARE SOME PEOPLE HAVING MORE SERVE SYMPTOMS THAN OTHERS?
The symptoms that people get depend on several variables. First, some people’s genotype makes them more susceptible to severe disease (at any age) from this virus than other people for reasons that are not yet clear. Severity of symptoms may also depend on the initial dose of virus – we are seeing particularly severe disease in those medical professionals with very close contact with patients – in anaesthetists or ophthalmologists for example. Finally age and underlying medical conditions particularly hypertension, obesity and diabetes are important. Men may get more severe disease than women (this tends to be the case with all infectious disease) and those with blood group A seem slightly more likely to have severe disease. Smokers are always at more risk from infection involving the lungs because their airways are already damaged. The reverse here is that those that display no symptoms may have only been exposed to a small amount of virus or are younger. Children in particular seem to be largely unaffected.
WHAT ARE THE TIMELINE OF SYMPTOMS AND WHEN IS HOSPITALISATION NECESSARY?
The timeline of symptoms seems to be about a week of fever and cough at which point either people recover or they develop secondary bacterial lung infections, typically severe pneumonias. It is at this point that people need antibiotics, hospitalisation and help with their breathing and oxygen levels.
Fact or Fiction?
Do we need to boost our immune system towards this virus?
You do not need to boost your immune system in order to repel the virus, although a balanced diet, plenty of sleep and moderate alcohol intake are important in keeping it in tip top condition. Stress makes the immune system perform extra well in the short term, although long term stress does suppress the immune system. Famine can switch off the immune system completely which is why in history, famine is typically followed by plague. Most of us are extraordinarily well nourished.
HOW LIKELY IS IT THAT WE WILL SEE A VACCINE SOON?
The most effective immune system booster however is a vaccine. Unfortunately, that is at least 18 months away. There are a number of different potential or candidate vaccines. Coronavirus vaccines are tricky to develop and there are several different approaches; a weakened (attenuated) live virus, a dead virus, bits of the spikes, and DNA or RNA vaccines which trick body cells into producing viral proteins to which antibodies can then be made.
Thanks to astonishing advances in genomics, candidate vaccines were ready within hours. Several are now in first in man trials – these are safety trials, involving a couple of dozen people at most. Then come Phase 2 trials involving several hundred people. At this stage, people may show evidence of antibodies to SARS CoV-2 but this is not the same as protection from it. This is proved in the final Phase 3 efficacy trials which involve thousands of people. Trials may – and indeed do – fail at any point. Many of the candidate vaccines involve new technologies and regulators are likely to be cautious. Hence the likelihood of a vaccine being at least a year away. And then there are all the issues of manufacturing capacity, distribution etc.
DO WE HAVE ANY EXISTING DRUGS WHICH MAY WORK?
More promising is the repurposing of existing drugs including anti viral’s typically used for Ebola or HIV and even the anti-malarial drug chloroquine or hydroxychloroquine. Many different approaches are being tried but people should be wary of people that claim miraculous efficacy for their vitamins or other products. They are usually more interested in the money than the evidence or the science. Any website that has the line ‘this is the secret that big pharma doesn’t want you to know’ is a scam.
Unlike H1N1 (bird flu) which was particularly severe in pregnant women, SARS CoV-2 does not seem to affect pregnant women more than other people of the same age and there is no evidence so far of vertical transmission (direct from mother to baby during pregnancy). Those babies that do get COVID-19 seem to do very well.
AFTER I HAVE HAD THE VIRUS, WILL I BE CONTAGIOUS TO ANYONE ELSE AFTER THE ISOLATION PERIOD?
There is much still to be learned about this virus but information to date suggests that the virus may persist for up to a month after infection. However virus cannot be grown from samples taken from infected people after about 10 days suggesting that tests may be detecting dead virus. The 14 day quarantine period reflects this.
THE GOVERNMENT ARE TALKING ABOUT ADMINISTERING ANTI-BODY TEST’S. CAN YOU EXPLAIN A LITTLE ABOUT THIS?
There are two types of testing; a direct test to see whether the virus is present (using a technique called PCR to amplify the tiny amount of RNA likely to be present in a swab sample) or a test to see whether antibodies are present. This will tell you if you have had COVID19 in the past. Confusingly, since antibodies may not appear for 5 – 7 days after infection, you may get a negative antibody test at the beginning of an active infection. Having been involved in pandemic planning for H1N1, I strongly suspect that there are far more cases of COVID19 than we are aware of, with hundreds of thousands of people infected, rather than thousands in any one country. Only extensive antibody testing will tell us whether this is true or not.
WILL WE SEE THIS VIRUS RE OCCUR LATER THIS YEAR?
We will almost certainly see a second wave of cases in December/January in the Northern Hemisphere but by then, I think that we will have much advanced testing and contact tracing. It is noticeable that those countries that seem to have contained COVID-19 most effectively are those with the most aggressive testing and contact tracing regimes, allied to isolation and quarantining.
This acute period will come to an end. CoV-2 will become yet another circulating virus continuing to pick off the older and sicker amongst us. And the world’s population will begin to develop immunity. We are an ingenious species, we have the ability to work this out provided we collaborate, nationally and internationally. There is light ahead, however dark the tunnel may seem at the moment.
FURTHER INFORMATION
If people want more, URKI have just set up this site with the Chief Scientist, Patrick Vallance, which Vivienne is helping with. OR click here for Vivienne personal website.
Vivienne Parry, OBE