Covid controversies. The jury is still out on some key issues.
Nine months in, Covid research is still in the messy phase. While the planet waits impatiently for dependable scientific consensus on the prevention and treatment of the pandemic, medical research disagrees on several issues still. Here are some of the key Covid controversies that medical science is still wrestling with now – and the state-of play for each.
Do children spread the virus?
Schools were preventatively closed at the beginning of the Covid-19 epidemic due to the belief that the virus would spread rapidly among children, as is the case with flu. However, due to the fact that children don’t get particularly sick with Covid-19, it was then postulated that they are not particularly infectious and transmission studies concluded that children were much more likely to contract it from their parents than the other way around. School teachers too seemed less likely to contract the illness from the young. A strong lobby to reopen schools followed.
In line with the findings, Israel optimistically opened up their schools in May. At this time the country was experiencing only 100 new cases a day. The reopening of Israeli schools proved to be disastrous. One school quickly flooded both its own and surrounding communities with new cases. Last week two articles were published measuring the quantity of virus in the nasal passages of children under five years old in the USA; concluding that the sampled children have RNA viral loads greater than 100 times than seen in adults. This implies that young children may be important drivers of infection, like they are with flu and RSV. Some South African academics currently feel that this doesn’t necessarily translate into a greater possibility of transmission, but opinion is likely to change with this strong new evidence.
The Israeli experience has resulted in Israel’s shift to a slow reintegration into schools, much like we in South Africa are doing now. The low case numbers in Israel gave its government an initial illusion of control which influenced it’s decision to reopen schools. However, as later witnessed, it only took one small center to ignite a local outbreak. Another salient issue is that children will become more important for immunization targeting. This is a problem because children and pregnant women are usually the last population groups to be tested regarding vaccine safety.
Is the virus airborne?
To the layman it seems obvious that the virus is airborne because it is spread by coughing. But the scientific question is less obvious. If the virus is truly airborne (not attached to droplets) then it can remain in the air for several hours and be spread by air conditioners and in aircraft. There are obvious sanitizing implications here.
While there is no certainty, only in July did the WHO concede that this may be a factor regarding indoor spread. Confirming this recently is a report of a recent outbreak in an Old Age Home that has been linked to airborne transmission through the air-conditioning.
Masks, -do they prevent spread?
Many studies have shown that masks do not prevent the spread of influenza. There are some studies that indicate that masks are an effective Covid-19 barrier, but there is no absolute consensus. Many health authorities however are convinced that they do work and countries with cultures of mask wearing guidelines seem to enjoy significantly lower mortality rates. Double layer cloth masks will almost certainly reduce the spread of droplets and, combined with social distancing, will probably help to reduce viral dispersion. Fresh air may become the new prescription as there are very few reports of people contracting the virus outdoors. Remember that the main purpose of masks is to protect others should you be in the infectious window prior to becoming sick. Those pretty masks with a vent at the side do not curtail droplet spread and are now banned in many centers around the world.
Controversy also abounds in the sense of false security that wearing a mask may protect you. A recent hamster study where the hamsters were protected by mask material from an adjacent cage containing coronavirus-infected hamsters shows that there actually is some protection for the wearer.
If anything, wearing masks may reassure many people by implying that you are fastidious with prevention and will help alleviate anxiety in our community, – a small price to pay.
Can you treat Covid-19 with Hydroxychloroquine (HCQ)?
Test tube studies 15 years ago showed that HCQ can interfere with viral replication of SARS in a laboratory setting. Furthermore, when Zinc was shown to have promise as an antiviral supplement, HCQ was believed to facilitate the entry, concentration and anti-viral effect of Zinc inside the cell. HCQ has been around for nearly 90 years and has an excellent safety profile when used in low doses for long periods of time for a variety of conditions; which is why it was considered a promising candidate for treating Covid-19 cases. Anecdotal reports and studies out of Korea and China in February and March encouraged Western centers to start using it – especially in hospitalized patients.
In June, a large collaborative review of data by the WHO of hospitalized patients proved that HCQ gave no benefit in high doses and actually contributed to the death of some patients. Two other studies agreed on this, though one has since been withdrawn. This evidence led to the immediate withdrawal of HCQ in further treatment of patients in hospitals. The arm of the trial assessing the use of low doses as outpatients and preventative dosing was not stopped. A strong trial using HCQ post-exposure was published on the 6th August, proving no benefit to exposed people who were not sick yet; another nail in HCQ’s coffin!
Despite the strong evidence, Trump has not changed his stance on HCQ and many doctors are refusing to enter the debate because of the political fallout that it may bring them. Some doctors are still using it in low dose preventative strengths (200mg/week vs. 2400mg/day in ICUs) and some academics in the USA, Europe and Far East claim there may still be valid reasons for this. Preventative HCQ use among Indian healthcare workers reduced hospital admissions especially when used for prolonged periods of time. Swiss death rates went up dramatically when HCQ was banned in the EU in May, only to drop again in June when unbanned- an interesting observation. There are still several preventative trials underway that should end by October and hopefully we will have a conclusive answer soon. Until then, there seems little reason for high risk persons not to take it together with Zinc once a week.
As this controversy fades, another possible candidate has risen: A veterinary medication, Ivermectin, used for treating parasites has been mooted as the new ‘cure’. Positive effects as well as the first trials refuting its use are now entering the fray, watch this space…
Are infrared thermometers Ray-Guns?
No controversy here: These thermometers measure heat waves radiated by the body proportionate to your temperature and impart no radiation to the person whose temperature is being measured- another fake news sensation.
Lies, damned lies and statistics:
Thanks to significant differences in reporting protocols across the world, there are large differences in infection rate statistics that make it difficult to model the disease spread reliably. Some countries report infection rates as high as 50% of the total population while others register a rate as low as 1%. The significant differences in the disease prevalence and rate of spread make it difficult to get a handle on the contagion. But the wide swings in the statistics are likely to have less to do with actual infections and more to do with the variability of reporting protocols, testing processes, social attitudes and norms in each country. A recent study indicates that only 35% of Covid cases get reported in the USA and that the reporting of cases in other countries is even lower – suggesting that the global footprint of the contagion might be well understated.
Scientists use two main approaches to predict the spread of Covid. One way is to test a sample of the population for antibodies and express the numbers as a percentage of the total population. Some recent antibody studies suggest that only 14% of people in the UK have had COVID-19, compared with 19% in Sweden. Another method is to mathematically model the data to project the probable prevalence of the virus. Depending on the method used, distinctly different statistics could be produced. If the data flowing in from countries is inaccurate, the models will be too. The relevance of all of this will come to light when deciding what comprises a high enough level of immunity in the community to say that our herd is safe. South Africa has only approved antibody testing for vaccine trials, so we can’t compare data with other countries. With possible T-Cell cross reactivity from other Corona viruses, we may need a little as 20% to end the epidemic, but vaccinologists are claiming that we will need 70% of the population to be immune before we are safe from future waves. The answer is coming…
When in doubt, check in with your GP. Stay safe.
Dr Mark Holliday/ StoryCo August 13, 2020