Category: Health

When Covid-19 cases began to rise in the U.S. in March, testing was a major point of contention. There were differing opinions as to whether enough testing was or could be done. A lot of testing was delayed after it became clear that the tests developed by the CDC were faulty. In an effort to counteract this shortage of tests, the FDA allowed many test kits to be sold without any validation. This led to perhaps an even worse situation. A detailed report by 60 Minutes shows what a disaster this was.
https://www.cbsnews.com/video/coronavirus-antibody-testing-inaccurate-data-60-minutes-2020-06-28/

With the pandemic in the U.S. spreading so rapidly since June, many people do not believe it is possible to test enough people and get results fast enough to control the virus. Most states are far below the minimum testing target.
https://www.nytimes.com/interactive/2020/us/coronavirus-testing.html

However, this conclusion is based on the testing technology that is currently in widespread use, namely a molecular diagnostic test of a nasal or throat swab. There are other techniques that are much more efficient, faster and cheaper. These may be able to close the current testing gap so that testing can be used to get better control of the virus and reduce how fast it is spreading.

Pooled sampling combines samples from several people and tests them in a single test. If the test is negative, it saves testing each of the samples. If the test is positive, then each sample does need to be tested. This technique was actually developed during World War II. Basic pooled testing was given “emergency use authorization” for Covid-19 testing by the FDA on July 18, 2020.

But there are newer more efficient pooled testing techniques. Using a mathematical model based on a “hypercube” can minimize the number of tests needed to isolate the positive cases and so can use larger sample sizes. This approach has been successfully used in Rwanda.
https://theconversation.com/rwandas-covid-19-pool-testing-a-savvy-option-where-theres-low-viral-prevalence-141704

Another very promising direction is cheap at home tests. This will allow very large scale testing without the detrimental time delays of waiting for a lab to process the sample. The following reports a really simple and fast test that is in late development. You simply spit into a test tube and insert a paper strip that will change color in 15 minutes if the virus is detected.
https://www.nytimes.com/2020/07/03/opinion/coronavirus-tests.html

New testing techniques such as these are potential “game-changers” in controlling the spread of the coronavirus.

There is a growing sense in the U.S. that the epidemic is now unstoppable. Each state, city and rural area has their own crisis. Hot spots can suddenly turn up anywhere. A small outbreak in Alaska has been one of the country’s fastest-spreading for three weeks, while transmission in Texas and Arizona has slowed.

Perhaps 10% of the infected account for 80% of new cases. Unpredictable super spreading events in nursing homes, meatpacking plants, churches and bars are major drivers of the epidemic.

Contact tracing is moot, there are too many cases to track.

None of the medicines for which hopes were once high (AIDS drugs, antivirals and malaria drugs) have proved to be cures. Experts familiar with vaccine and drug manufacturing are disappointed that, thus far, only dexamethasone and remdesivir have proved to be effective treatments, and they are limited to special circumstances.

Read more at
https://www.nytimes.com/2020/07/29/health/coronavirus-future-america.html

Six months of a global pandemic have stirred an unprecedented amount of research. While many things about Covid-19 have been discovered, a lot of research has produced incomplete and sometimes contradictory results.

These are the pressing questions that do not have answers yet.

1. Why do people respond so differently?

Some people have mild symptoms or even no symptoms and don’t know they are infected. While most reactions are respiratory there are also cases of heart and blood vessel damage and kidney failure. Many people require hospitalization, some end up in an Intensive Care Unit (ICU) and many people die from Covid-19.

2. What’s the nature of immunity and how long does it last?

Studies have found that the level of antibodies produced by the immune system when someone has been infected with Covid-19 can vary quite a lot. It is not known what level of antibodies are necessary to provide immunity or how long it lasts.

3. Has the virus developed more dangerous new mutations?

Molecular biologists can determine the genetic mutations in Covid-19 and use this information to track how the virus has spread from one region to another around the world. But it is not known if any of these mutations are more virulent or transmissible than others.

4. How well will vaccines work?

Some vaccines might work well at preventing lung infections but not infections elsewhere in the body. Some vaccines may produce enough antibodies to work for some people but not enough to protect others from infection.

5. What is the origin of virus?

There is general agreement that the virus originated in bats. Scientist are able to compare the Covid-19 genome to the genomes of coronaviruses found in different bats and other animals. So far, there are genetic differences that are too large to conclude what the original source might be.

For a more complete report on these questions and the research that has been done see
https://www.nature.com/articles/d41586-020-01989-z

Television news loves to show pictures of crowded beaches as examples of how people are ignoring social distancing guidelines. In some cases this may be true, but in many cases they have just lost perspective.

Here’s a photo of a beach that looks overcrowded.

But that’s because you are looking at a long stretch of beach along the shore line.

When you look at the same beach, looking towards the water, you can clearly see that there is easily more than 6 feet between groups of people.

The responsible way for television to report overcrowding at a beach would be with an aerial view.

As lockdown restrictions are relaxed and people go out more, what is the probability of actually encountering someone who has Covid-19 and is contagious?

Someone who has Covid-19 is infectious for 14 days but may not show symptoms for first 5 days (the mean). Once they have symptoms they will be either in quarantine or in the hospital. So your risk of encountering someone who is contagious is during the 5 days before they had symptoms. But there is no way of knowing how many such people there are, it may take up to 5 days before they have symptoms and can be counted. As a good approximation you can use the total number of new cases in the last 5 days.

In addition, many cases are unreported because people do not have any symptoms (asymptomatic) or their symptoms are so mild that they don’t realize they are sick. So add 10 times the total 5 day case count to include the unreported cases, based on this CDC analysis.
https://www.nytimes.com/2020/06/27/health/coronavirus-antibodies-asymptomatic.html?referringSource=articleShare

Then divide by the population of your location to get the probability that any random person is infected.

For Toronto this probability is .07% about 7 out of 10,000.

Rather than meeting a single person, what about meeting another couple at a restaurant where there are two more couples at adjoining tables and one server?

Using high school math you can calculate the probability that one or more of these 7 people are contagious.

This probability is .5% about 1 out of 200.

This is a fairly low risk of encountering someone who could infect you. There is additional risk of airborne infection but not enough is known to estimate its probability (see previous blog).

But the more people in a group, the higher the probability. If you go to a house party where there are 25 other people, the probability that at least one person is contagious is 1.7%

Low probabilities do not mean that you can skip the social distancing rules. If everyone does that it will increase the spread of the virus, slowly at first since it is low probability but more rapidly as cases increase and the probabilities increase.

On July 9, WHO (World Health Organization) acknowledged that the coronavirus can spread through tiny droplets floating in the air, after more than 200 experts in aerosol science complained that the agency had failed to warn the public about this risk.
https://news.yahoo.com/pandemic-exposes-scientific-rift-over-204543074.html

There were a few early cases of Covid-19 that suggested it was transmitted by airborne particles. A very dramatic case was the choir in Washington state that held a rehearsal with 60 members on March 10. Three weeks later 45 people were infected and two died.
https://www.latimes.com/world-nation/story/2020-03-29/coronavirus-choir-outbreak

This risk of airborne transmission is highest in crowded indoor spaces with poor ventilation and may help explain super-spreading events reported in meatpacking plants, churches and restaurants.

What can you do to reduce your risk of exposure to airborne transmission?

– Avoid crowded indoor places, close-contact settings and confined spaces with poor ventilation.
– At home, open windows and doors whenever possible.
– Upgrade the filters in your furnace/air-conditioning system and adjust the settings to use more outdoor air.

https://www.nytimes.com/2020/07/06/health/coronavirus-airborne-aerosols.html

Canadian news about Covid-19 has generally been pretty positive about the progress being made to contain the virus across Canada.

American news has been obsessed, for good reason, about the outbreaks occurring all over the country.

But you don’t see many reports about Europe. Many countries in Europe had major outbreaks before we even saw very many cases in North America. They have contained the virus far better. Our health “experts” probably could learn a lot from the Europeans, but I’ve never seen any indication that they communicate with them very much. This is doubly true for Asia. Many Asian countries have done a far better job from the beginning than Europe and certainly North America (noted in several earlier blogs). When’s the last time you saw an Asian virologist interviewed on our news?

Here’s the proof in pictures.

U.S.

Canada

Italy and Spain had the worst outbreaks in Europe, but they have brought their cases down much faster than Canada and to a much lower level.

Italy

Spain

If you want to see comparisons with other countries, you can see summary charts for every country in the world here (scroll down a few pages).
https://www.nytimes.com/interactive/2020/world/coronavirus-maps.html#countries

It seems clear now that many States that opened too early at the end of May has led to an increase in Covid-19 cases in the US.

By contrast, in Canada where opening has been more gradual and is still in progress, new cases continue to decline.

Many states (red on map) are seeing increases in the daily number of cases. The three largest states in the US — California, Texas, Florida — are setting records for the highest number of new daily cases since the pandemic began. Texas has just started to reimpose some lockdown restrictions. Many other states will likely be forced to do the same.

https://www.youtube.com/watch?v=kcaMSmD-3Wc&feature=youtu.be&t=73

This spike in cases does not disprove the alternate theories reviewed in the previous email, which basically held that the virus would not spread at epidemic rates because population immunity had become 50% or more. Those theories could still be true and in the US the virus is spreading because their immunity level is under 50%. 

These alternate theories used UK data to arrive at the conclusion that immunity in the UK could be more than 50%. The real test of these theories will be what happens in the UK. The UK is still in various stages of lockdown, but on July 4, pubs, bars and restaurants reopen. If people do not adhere to social distancing guidelines, there could be a spike in cases, as in the US, or there could be no spike if the theories about immunity in the UK are true. 

Indications are that social distancing guidelines will not be followed very well, as seen in the rush to Bournemouth Beach last weekend. This is similar to scenes from California and Florida.

In the June 3 post, I expressed a strong opinion that the health authorities have bungled dealing with face masks and that they should be strongly recommended.

It turns out there are Open Letters to Dr. Tam (Chief Public Health Officer of Canada) and the top health officials in Albert, Ontario and Quebec recommending mandatory face masks under specific conditions. To date there are about 1400 people who have signed these letters, almost all are health practitioners and it looks like more than 50% are MD’s.

You can read the letter at https://masks4canada.org/33-2/open-letters/
To sign, click on a letter, scroll to the bottom of the page and click To sign up

In epidemiology as in most sciences, there is a prevailing conventional view and then there are other unconventional views.

In North America we are currently following the conventional view based on the research done by Neil Ferguson and his group at the Imperial College London, which I have referenced several times. According to this view, various social restrictions must be imposed to prevent the epidemic spread of Covid-19, with a primary aim to flatten the curve so that the health care system is not overwhelmed. The interpretation of where we are now, according to this view, is that as many locations in the US and Canada are opening too early, there will be another series of outbreaks that could reach epidemic proportions and will require another period of lockdown.

However, in the UK, there is a lively public debate about a number of other views. For some reason, the British media thinks its audience is intelligent enough to follow these scientific theories, whereas here in the “colonies”, we hear very little about them.

Sunetra Gupta and her group at the University of Oxford published research in March around the same time that the Imperial College of London released its report. In their view Covid-19 was circulating for quite some time before it was recognized as a pandemic. In the process, the Oxford research showed that many people had acquired immunity through these early unrecognized cases. Gupta argued that in fact the level of immunity was high enough to slow down the spread of Covid-19 without the extreme social measures and lockdowns imposed in the UK and other countries, and that the Imperial College model was an overreaction at an extremely high cost. https://unherd.com/2020/05/oxford-doubles-down-sunetra-gupta-interview/

Another theory being proposed by distinguished scientists Michael Levitt and Karl Friston, is that not all people are susceptible to Covid-19 because some have resistance. This may be due to past immune responses to other coronaviruses like the common cold. There is evidence that as much as 50% of the population has some of this resistance to Covid-19 at the T-cell level in the immune system. This means that Covid-19 will not spread as rapidly as when 100% of the population is susceptible, a typical assumption made with new viruses.
https://unherd.com/2020/06/karl-friston-up-to-80-not-even-susceptible-to-covid-19/

This video gives a good explanation of how this resistance may work in the immune system.
https://www.youtube.com/watch?v=fN3UmKSVCZ8&feature=youtu.be&t=133

While the UK research focuses on the UK and Europe, the same principles would apply to North America, just the numbers might be different.In our Covid-19 model for Canada, setting an initial immunity of 50% results in a rapid decline in cases that does not match actual case counts. With an initial immunity of 30%, we get a much slower increase in cases than when initial immunity is 0%, so that reimposition of lockdown is not needed until Dec 2021 instead of Sep 2020.

So if these contrary theories have merit, we may not see large outbreaks of Covid-19 in the ensuing months. In spite of increasing cases in a number of US states this week, it is too early to conclude that there will be epidemic outbreaks leading to a second wave requiring another period of lockdown.