Squiz Shortcuts – Vaccines
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A vaccine for the coronavirus is being held out as the thing that’s going to get the world back on track. But developing it and then getting people vaccinated is complicated. In this episode of Squiz Shortcuts we look at what a vaccine is, how it’s developed, and the challenges public health officials are facing with developing one for COVID-19.
When was the first vaccine developed?
It’s thought that the first vaccine was developed in 1796. Dr Edward Jenner in the UK discovered that immunity to smallpox could be brought about by giving people material from a cowpox lesion. He called the material ‘vaccine’ which comes from the root word ‘vacca’, which is Latin for cow.
And historians say the history of innoculation – this is to give people a material to produce immunity against a disease – goes back even further than that, to the mid-1500s. A Chinese text from 1549 described healthy people snorting powdered smallpox scabs in order to develop a mild case of the disease and get immunity.
What is a vaccine?
A vaccine is a medicine that prevents disease for a period of time or for life. Most medicines treat or cure diseases, but a vaccine’s purpose is to stop us from contracting the disease in the first place. And that works when we’re given a medicine that has the same germs that cause the disease, but those germs are either killed or weakened to the point that they don’t make you sick. A vaccine stimulates your immune system to produce antibodies, exactly like it would if you were exposed to the disease. After getting vaccinated, you develop immunity to that disease, without having to get the disease first.
How is a vaccine developed?
The development of a novel vaccine – that’s a new vaccine from scratch – is a complex and lengthy process. But long story short, technicians identify the disease’s antigens and then they tinker with them so they can’t reproduce themselves, or at least do it very slowly. They grow and purify the antigens. And then other ingredients are added to turn it into a product that can be given to patients. And then there’s rigorous testing in the lab, on animals, and on humans.
From starting that research effort to production, it generally takes 10 to 15 years to develop a vaccine. That’s if they are able to crack the code at all. For diseases like HIV, they haven’t yet. And even when a vaccine is found, not all last forever. For example there are some where we need to go back and have boosters because the protective response wears off over time.
What’s herd immunity?
Mass vaccination programs don’t just protect those individuals who are innoculated, they also give a high degree of community protection for those who aren’t. That’s called herd immunity, and it prevents subsequent waves of infection from becoming too intense. The % of the population that needs to be vaccinated to provide herd immunity varies disease to disease. For measles it’s about 95%, and for various strains if the flu it’s 30-75%. It depends on how infectious the disease is. It’s important to note here that the other way for herd immunity to a disease to be developed is to let the disease spread to let the population to build the antibodies that offers protection against contracting it again. Herd immunity can be developed by enough people becoming infected with a disease. That works if you can survive it, and if can’t contract the disease again.
What’s the talk about herd immunity and COVID-19?
Since COVID-19 has made its way around the world, there has been discussion about developing herd immunity by allowing COVID-19 to make its way through the community. The problem with that is COVID-19 is highly infectious and the death rate is of a level that health officials can’t accept. Also it’s a new virus and medicos are still working out how its affecting people who have had it, and whether they can re-contract it because there’s some evidence that our antibody response fades pretty quickly. So the alternative is a vaccine.
How realistic is it that we’ll have a vaccine in just a year after COVID-19 emerged?
According to the experts, it’s possible. There is hope that the unprecedented concentration of the world’s top scientific minds on COVID-19 will deliver a vaccine in an incredibly short timeframe. The New York Times has a tracker on these efforts, and there are some 165 potential vaccines under development, with come 30-odd having progressed to human trials. Human trials are an important phase of the development of a vaccine for obvious reasons. It’s one thing to know how a medicine works in the lab, but testing its safety and efficacy on humans – that is, working out if it’s effective – is an important stage. And right now there are six vaccines in phase three of trials. Phase three is when the vaccine is tested on thousands of people across different nations and demographics to answer the most critical question of all – does it protect people against coronavirus?
What are some challenges with the development of a vaccine for COVID-19?
COVID-19 isn’t going to go down without a fight. Despite all the scientific evidence so far there is no guarantee a trial will be successful. For example there are big questions about how long an immune response will last in those who are vaccinated or those who have been infected with COVID-19. And that’s why experts say it’s important that all those efforts continue, because we don’t know which trials might stumble in the human trial phase.
It’s also why there’s lots of chat about the international research community sharing data, something that is happening but there is a concern that’s growing – and that is how a vaccine, when one is available, might be shared across the world. Those concerns are focused on what’s called vaccine nationalism. The World Health Organisation says rich nations have a responsibility to share any vaccine that is eventually produced globally. That of course is going to cost a lot, and it comes on top of significant government funding towards the development of a vaccine that nations like the US and also Australia have provided. They’re going to want to protect their own people. And they’re being asked to help other nations, particularly poorer nations. For our part, PM Scott Morrison has already committed to sharing a vaccine with the world if Australian researchers come up with the vaccine.
What’s the deal with the anti-vaxxer movement?
The anti-vaccination movement is really having a moment. There are some with hardcore conspiracy theories that the coronavirus is made up and it’s an attempt at government control. Coming down a notch, there are those who believe that vaccinations do harm, and estimates put that at 2-3% of Australians. That’s incredible mild compared to what’s going on in the US where recent polls have found as few as 50% of people are committed to receiving a vaccine, with another quarter wavering. Reports have suggested that half the American population aren’t convinced they’d get a coronavirus vaccine. Mistrust in vaccines has been growing in the US in recent years. It’s a sentiment that resists categorisation by political party, educational background or socio-economic demographics. And it’s complex. Some are inspired by anti-vaxxer celebrities. Even US President Donald Trump has expressed concerns about vaccination in the past. But there’s also concern about how fast the coronavirus vaccine is being developed and whether it would be safe. And that’s just the start of it. It’s called vaccine hesitancy. And it’s a real worry for public health officials because the coronavirus vaccine will only work if enough people get it. The more contagious the virus, the more immune people you need for it to be effective across a community. Some experts say that the ideal level is about 70% of the community will need to be vaccinated for coronavirus for it to be effective and driven into the ground.
What about if a vaccine doesn’t work?
The World Health Organisation says we may never have a “silver bullet” for coronavirus. And that’s why experts point out that if a long lasting vaccine isn’t on the cards, we’re going to have to test and treat people efficiently if we’re going to protect our health, open up our economies and get our pre-COVID lives back on track.