The urgent need for a vaccine to protect us from COVID-19 is obvious. Scientists have produced some promising candidates but, as so often is the case in this pandemic perceived political imperatives are demanding ‘shortcuts’ in the development process that may hinder essential studies of efficacy and safety.
Science is yet to produce an effective vaccine to prevent any of the diseases caused by coronaviruses. While recovery from many viral infections is associated with long-lasting immunity, that is not the case with coronaviruses. We all know that the ‘common cold’, which is caused by a coronavirus, can trouble us time and time again.
Post-infection immunity is short-lived. We now have a number of reports of individuals who recovered from a Covid illness only to be re-infected months later.
Some encouraging progress was in evidence as scientists tried to develop a vaccine for the SARS-Cov virus in 2003 but the epidemic waned and research was suspended. Quite extraordinary advances in molecular biology have since occurred. To understand how these advances can be applied to help with vaccine development we need to discuss a few basic facts about our immune system.
Early in foetal life we begin the production of our immune system which must be able to recognise when something ’foreign’ enters our body. It would be too dangerous to have a system that could only recognise “non-self” after we first met it. With something dangerous we could be overwhelmed before we could respond. So remarkably, evolutionary processes have provided us with cells that can recognise virtually everything that we may encounter before we actually do so.
Things that may enter our bodies and promote an immune response are called antigens. There is a price to pay for having this huge repertoire of ‘antigen recognising cells’. As there are zillions of antigens to be recognised we only have a few cells that can recognise any given antigen. When cells do recognise the presence of ‘their’ antigen they react by multiplying exponentially so second encounters are responded to more rapidly and efficiently.
Vaccines are designed to safely provide that first encounter so we are primed to pounce on a subsequent encounter with antigens present in the vaccine.The SARS-Cov-2 virus responsible for the illness we refer to as Covid-19 has “spikes” on its surface that have developed a three-dimensional shape such that they can bind, key in lock fashion, with a structure found on the surface of cells lining our airways, throat, nasal passages and eyes and a number of other cells in our body. Once the virus has docked with the cell, a chemical reaction occurs that alters the spike such that it can actually cut a hole in the cell to gain entry.
As described above we do have immune cells that can recognise this spike protein but in some cases the immune response is too slow to stop damage to many cells before the immune system’s response is in full gear.
Most of the candidate vaccines are designed to introduce our immune systems to the spike protein so that if we were to be infected with the corona virus we would quickly recognise it jutting out from the surface of the virus and prevent it binding to the cells it wishes to infect.
There are variations in the way scientists are trying to stimulate a response to the spike protein. Some used killed virus plus an ‘adjuvant’, a chemical compound that is known to activate immune responses. Others are using just fragments of the virus.
Extraordinary advances in genetics have allowed scientist to study genes ( blueprints) for the SARs-Cov-2 virus. One vaccine actually involves administering the genes necessary for making the spike protein.
Vaccination results in an individual actually manufacturing the spike protein, recognising it and making an immune response.
China and Russia claim to have developed a safe and effective vaccine that they are using to immunise their citizens. It would be inappropriately condescending to dismiss these claims as both countries have outstanding scientists. However, there are no published data allowing Western scientists to review the methodology and results. Let’s hope they are successful.
At least 100 laboratories around the world are trying to develop a vaccine but collaboration between scientists in the UK, US and Australia have three ‘front runners’ ready to test on 30-40,000 people to determine safety and effectiveness. Preliminary studies with these vaccines look promising but one can say no more.
America is providing most of the money to support Western scientists chase a vaccine. For all countries, Covid-19 is causing massive economic losses and personal suffering but in the US, the country that has more infections than any other, President Trump is literally desperate to have a vaccine before the presidential election in November. He continues, almost daily, to claim there will be a safe and effective vaccine available ‘very shortly’.It’s not going to happen and we in Australia should be following containment strategies based on the likelihood that mid to late 2021 is the earliest date we could have a vaccine available.
As of today the US is betting on vaccines that are about to enter phase three trials on huge populations by funding the production of more than 300 million doses of vaccines that have not, as yet, been shown to work! If they don’t work then billions of dollars will have been wasted. Trump obviously thinks it’s worth the risk. Now comes news the US Food and Drug Administration (FDA) is considering giving permission to use these vaccine preparations outside of any scientifically conducted studies.
Such an unjustified approach runs the risk of undermining public confidence in the vaccine if unacceptable side effects develop. This is a huge problem because “anti-vaxxers” are already at work on social media urging people to avoid any Covid vaccine for any number of fanciful reasons. A recent survey in Australia suggested that about 20% of us would not agree to be vaccinated. The percentage of Americans with similar views is as high as 40%.
Some of our senior clergy have expressed concerns about the ethics of using vaccines where their preparation involved growing virus in foetal cells made available after an abortion. The cells involved have been growing in laboratories for about 30 years and the abortion in question was not in any way associated with future scientific investigations. The cells have actually been involved in experiments that saved lives. In the resulting publicity it seems most ethicists were very comfortable with us obtaining a benefit from the propagated cells.
We need to be preparing Australians for the arrival of a vaccine that has been demonstrated to be safe and effective. Our CSL has impressive manufacturing capacity for producing the doses of vaccine we will need. Australia is a partner in the development of a number of vaccines, with scientists at the University of Queensland and the Doherty Institute in Melbourne recognised for the excellence of their contributions.
Current intelligence strongly suggests that any effective vaccine will need to be administered more than once to achieve the desired immune response. We are likely to need at least 70% of the population vaccinated to terminate our epidemic. Immunising children will be very important as they are efficient spreaders of the corona virus and research this week tells us they can do so for extended periods of time even when asymptomatic.
There was much publicity recently after the Prime Minister suggested that vaccination might be compulsory, a position he quickly reversed. Early promotion of safety and benefits once we know a vaccine will be available should see us reach our 70% immunisation rate without more coercive tactics. Logically health-care workers and the frail elderly would be early targets for vaccination.
The world, especially the ‘developing world’, is in desperate need of a Covid vaccine. There is justified optimism that such a saviour will become available but to rush the process
and take short cuts that leave us uncertain about side effects or effectiveness could ruin the initiatives we need to enter a post-Covid world.