Boris Johnson’s call for wealthy nations to share Covid vaccines more equitably with poorer countries was vital. The warning from the WHO that “no-one is safe from Covid till all are safe” is a truism with major implications.
Viruses are considered one of the earliest creations of primitive evolutionary mechanisms. They are not ‘organisms’ with the capacity to reproduce themselves. Instead, they are composed of the blueprints for their reproduction that they must provide to a ‘factory’ that can follow the instructions and produce copies of the virus.
Like all viruses, SARS-Cov-2 attaches to and invades a cell that is capable of reproducing itself and diverts the production process to make copies of the invading virus.
Under evolutionary pressures viruses have realised it is not a good idea to simply clone themselves, i,e. make identical copies of themselves. Viruses constantly experiment to see if they can improve their capacity to invade hosts. It’s a random process so some changes may result in an inferior model but some ‘variants’ may result in a superior version. Change is also important as the host cells they invade may belong to an entity capable of making an immune response to the virus. Looking different is a good tactic.
The SARS-Cov-2 virus is known to have infected 110 million people, killing 2.5 million of those infected. As many people infected and infectious have few or no symptoms and testing regimens vary greatly, it is estimated that the real figure is likely to 20 times greater than that actually measured. Of course, with this virus multiplying billions upon billions of times, it is going to produce variants, some of which will provide it with new advantages.
Our pandemic is the result of these viruses developing a mechanism for attaching to specific cells lining the airways, mouths, noses and eyes of humans. All share a structure known as an ACE-2 receptor. This is a lock that, if opened, would allow a SARS virus to gain entry to cells in which it could multiply. Through trial and error the SARS virus has produced variants that have on their surface a ‘spike protein’. This is the key that will fit into the lock on the human cells described. Part of this spike protein can cut a hole in the cell to which the virus has attached, allowing invasion to occur.
Over the past 12 months viral variations on a theme have produced at least four new models with an improved capacity to bind to ACE-2 receptors. Imagine you had a key for a lock on a door. The lock and key were not perfectly aligned but you could get the door open with a few attempts and some patience. Imagine you get a replacement key that is a much better fit and can open the lock effortlessly. The four major Covid variants that are more infectious than the original model have refined the key they carry to more efficiently bind to the ACE-2 receptors. While no details are available the US is reporting the discovery of 10 new variants this week.
Available data suggests that the new variants are not, per se, more deadly than the original models. They are, however, far more infectious. A year ago, for example, for every 1000 SARS virions that were inhaled into our mouth 100 would actually infect us. Now we may have a situation where for every 1000 virions of the variant strain that enter our mouth, 800 may actually infect us. More infections are therefore likely to occur and that means more people who are particularly vulnerable will be infected, with an associated increase in mortality.
More infectious variants have been detected in Australia and there has been a massive and mainly successful public health response to limit viral spread. We are now in an enviable situation compared to so much of the world. However, clearly now only a successful global vaccination program can tame the pandemic.
So where are we at with vaccines?
The good news is that all the vaccines approved for use, including those produced by China and Russia, work. Some are better than others but all provide close to 100% protection from a Covid infection causing death or an illness requiring hospitalisation. While the Pfizer vaccine appears to block all Covid related illness, other vaccines may not stop people from developing symptoms of a severe “cold”. We can live with that.
It also appears that the vaccines provide protection from the variant strains so far identified. There is a real risk that this situation could change with new variations. The world is being immunised against the original strain of SARS-Cov-2 identified a year ago. Antibodies produced in response to a vaccine based on this original form may not be as effective in the future if the leopard makes very significant changes to its spots. We will need to look carefully at the need to reformulate current vaccines.
None of the vaccines has been shown to produce ‘sterilising immunity” I.e. stop the immunised from having viable virus reside in respiratory secretions. The presence of virus in such individuals poses no dangers to them but it does not stop the immunised from infecting the non-immunised. An obvious consequence will be the need, for the foreseeable future, to quarantine arriving travellers even if they have been immunised.
The safety profile of all the vaccines is reassuring. With more than 40 million doses of vaccine administered we have seen between 5 and 11 cases of allergic reactions per million vaccinations. As is true with most vaccinations a local reaction, sometimes associated with fever and fatigue that lasts a few days, is not uncommon after a second injection.
Unfortunately many anti-vaccination sites contain stories of severe complications. Any adverse event in the weeks after vaccination is documented and analysed by researchers. Given the millions of vaccinations and the vulnerability of many vaccinated older individuals from pre-existing co-morbidities, co-incidental problems in the weeks following vaccination are to be expected. Many anti-vaccination websites are using these to falsely claim that the vaccines are dangerous.
What don’t we know?
We anticipate but don’t know that immunity following vaccination will last at least six months. We will soon learn if annual vaccination will be required as with the influenza vaccine. We don’t know if those who have recovered from a Covid illness require vaccination but we are presuming that a booster shot would be a good idea. We need to know if it is safe to immunise children. There is no reason to expect that this should be a problem and we do know that immunising kids who are good viral spreaders would be desirable.
So the race is on. To end the pandemic we need a huge proportion of the human family to be immunised in a relatively short period. If vaccination efforts are prolonged immunity may wan before their chances of meeting up with the virus again are eliminated. History will judge us harshly if we allow local selfish imperatives to dominate the vaccination program for the world.
China’s ‘silk diplomacy’, with its supply of vaccines to poor countries, is much appreciated. All of us ‘haves’ need to act similarly. By promoting global equity we are supporting initiatives essential for our own self-protection. And in this hoped-for success we will realise how similar rather than different we all are.
Professor John Dwyer AO, is an Immunologist, Emeritus Professor of Medicine at UNSW and for many years heavily involved in efforts to improve the delivery of healthcare in Australia. He was the founder of the Australian Healthcare Reform Alliance.
Comments
5 responses to “The race is on … vaccines vs variants. The global response will determine the winner”
Why would the majority submit to a rushed, risky, poorly tested, genetic treatment, called a vaccine, which might kill them or leave them with permanent immune dysfunction and disease, and never used before against a virus which is no threat to 99.9% of people? Watch most people say no thanks.
Most people know –
While traditional vaccines work by exposing the body to a weakened strain of the microorganism responsible for causing the disease, these new Covid vaccines are mRNA vaccines, but they are not vaccines but genetic treatments.
mRNA (messenger ribonucleic acid) vaccines theoretically work by injecting viral mRNA into the body, where it replicates inside your cells and encourages your body to recognise, and make antigens for, the “spike proteins” of the virus. They have been the subject of research since the 1990s, but before 2020 no mRNA vaccine was ever approved for use.
Many thanks to Prof Dwyer for providing a layman’s information on covid-19. There are too many claims in social media on the efficacy of the vaccine that unless authorative source like Prof Dwyer could continue to educate the public, then there is less likelihood for fake stories to take root. Further questions for Prof Dwyer: (1) Is there any difference in the efficacy of the vaccine produced against the viral protein coat and the viral m-RNA. (2) Is it possible to mix the vaccines in (1)? (3) There appears to be different infectivity rate in different countries. Hence, is there any evidence to suggest that the virus has a preference or more sucessful in in infecting a person of a certain”race”? (4) Can one make a vaccine with a cocktail of all known variants from countries with high infection rate?
Yes, the race is on, humanity vs profits!
The planet’s common enemy is the virus and they don’t need a passport to taravel anywhere on earth. Without global collaboration, this pandemic will be with us for a while until the herd immunity sets in. The score then would be Virus 1, Man 0.
None of which explains how Covid can be such a threat when it is no risk to the vast majority of people. Even Professor John Ionnadis, one of the world’s top epidemiologists said it was no threat to 95% of people and other experts have said 99.9%.
Most of those who test positive have no symptoms, or symptoms so mild they are not sick and most who get sick recover. Covid is something most bodies can cope with but we do not know if that is the case for these vaccines. When did science-medicine lose common sense?
Thank you Anthony. Here are the answers to your questions. All the vaccines are designed to produce an immune response that stops the ‘spike protein’ ( the key) from locking onto and subsequently invading human cells. The mRNA vaccines have the person vaccinated making the spike protein. When this happens a vaccinated individual’s immune system recognises that this is not ‘self’ and makes antibodies that would neutralise any SARS virus entering the body and inhibit the spike protein. It is possible to mix the vaccines but more research is needed to see how beneficial this may be. Theoretically giving a first dose of a vaccine such as the AstraZenica one followed by an mRNA vaccine is an attractive possibility.Disadvantage not race determines vulnerability To date all the vaccines appear to produce protection not matter what variation is presented. This is particularly so with the Pfizer and Moderna vaccines.
Except…..
Vaccine development is a slow, laborious process. Usually, from development through testing and finally being approved for public use takes many years. The various vaccines for Covid have all been developed and approved in less than a year.
While the media are quick to offer “explainer” guides, which cite “foresight, hard work and luck” as the reasons we got a Covid vaccine so quickly “without cutting corners”, they all leave out key information.
Namely, that none of the vaccines have yet been subject to proper trials. Many of them skipped early-stage trials entirely, and the late stage human trials have either not been peer reviewed, have not released their data, will not finish until 2023 or were abandoned after “severe adverse effects”.