Update on Covid-19: Long Covid and vaccines


Guptadana writes to update Puri’s article published on October 9, 2020.

This article is intended as a footnote to this article:

There are few certainties about this coronavirus. One of them is that we are finding out new things all the time and our ‘knowledge’, or rather ‘understanding’, is constantly changing and being updated. After all, 10 months ago almost nobody in the world had ever heard of SARS-Cov-2, the virus which causes Covid-19. Now there are books, articles, posts, blogs and web pages full of information / misinformation of differing degrees of accuracy, and it is currently the most studied virus in the world.

Since Puri wrote his article, it has become clear that there is a growing phenomenon called ‘long covid’ emerging and the median age of those affected is 45. A good report on this was recently published by Tim Spector, Professor of Genetic Epidemiology at Kings College, London and others, Long Covid: Reviewing the Science and Assessing the Risk, which suggests that chronic disease may be more common in the younger population with severe long-term implications. Another Dutch report has reached similar conclusions and an article in this week’s New Scientist magazine reports that “there could already be millions of people around the world living with long covid.” Younger people may therefore also need protection from infection to avoid this potentially serious danger.

It is also becoming clear that vaccinating only the older age group would not generate herd immunity (where there are too few vulnerable people left in a population for the virus to infect) though it could still be immensely useful in limiting the spread of the disease. It is likely that, depending on how effective the vaccine is (its ‘efficacy’), a larger proportion of the population would need to be immune.

To create vaccines in response to these new emergencies, there is a new technology which has been developed to get human immune systems to react to just part of the outer coat of the vaccine, a protein called the spike. If our immune systems can de-activate the spike, the virus can’t get inside human cells. The code for making the spike protein is part of the virus’s central core and is stored in a chemical called RNA. The new mRNA vaccines depend on getting a small part of that code into cells for the sole purpose of manufacturing the spike, but no other part of the virus (e.g. the core material). Once the spike is manufactured, our immune systems detect it and produce antibodies which can be used to combat any future virus infection.

(Other viruses use another molecule, DNA, as the genetic material to reproduce themselves. DNA is the same genetic substance – though not using the same codes – as humans have in their cells.)

There are complicated technical differences between RNA and mRNA. mRNA is used to transfer information about the manufacture of proteins (in this case virus proteins) in the human cell. It does not enter into the human cell nucleus nor integrates with the human DNA. This means that this new technology of mRNA vaccines is thought to be comparatively safe. This is a link to an excellent scientific review of the technology of mRNA vaccines which comes to the conclusion that “both conventional mRNA and self-amplifying mRNAs cannot potentially integrate into the host genome and will be degraded naturally during the process of antigen expression. These characteristics indicate that mRNA vaccines have the potential to be much safer than other vaccines and are a promising vaccine platform.” In other words, the mRNA doesn’t become part of the human cell and rapidly disintegrates after completing its job of creating the spike.

Both the vaccine being developed by Oxford University / AstraZeneca, and the one developed by Moderna use different variations of this technology. There is a good summary of how these technologies work in this article. In addition to these two, not including vaccines being developed in China and Russia, Johnson & Johnson are testing a vaccine similar to the Oxford University one and Pfizer and Biontech are collaborating on an mRNA vaccine. All four are nearing the end of their final ‘Phase 3’ trials. For very good safety reasons, the results of these tests are sealed and even the scientists involved with them do not know the results until a specific number of cases of Covid-19 are reported in the trial participants. It is expected that some of these results will become available in the next few weeks and we can then see from that data how effective and safe these vaccines appear to be.

There is one final question around a risk from auto-immune diseases from vaccines. There have been cases of these kinds of diseases arising from vaccination, most famously that of flu vaccines in the 1970’s being associated with a very rare and serious condition affecting the nervous system called Guillain-Barre Syndrome (GBS), after a mass vaccination programme to curb the risk of a flu pandemic. In some studies it was shown to have caused GBS at a rate of 1 case per million vaccine recipients. However, it’s important to know that natural influenza infection causes GBS in 17 per million people infected.

Because mRNA vaccines don’t reproduce the virus’s RNA, because they don’t enter the nucleus of the human cell and its DNA code, and because the mRNA degrades naturally during spike protein production, it is difficult to see how any potential auto-immune disease would arise and so impossible to assess any risk.

It is my hope that Puri’s article and this update will help clarify some misunderstandings about this virus and current medicine’s response to it. We all, of course, have the freedom to make our choices about how we personally respond to the challenges it poses us as individuals and communities, and my sense is that at a physical level it is helpful for those responses to be as informed as possible.

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Guptadana (Gupi) has a degree in microbiology and a master’s degree in applied cell science and virology. He now works as a business consultant and an occasional blogger. abirdsong.blog

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