In my last post I went through the clinical trial process and why it is a stretch for are pollies to be promising to answer all our prayers, defeat the virus and return our lives to normality with a vaccine. Here I will expand on that.
As they get closer and closer to the releasing a vaccine, you’ll hear two words more and more. They are safety and efficacy. The problem is that those words are not absolutes. In regards to safety, there is not a medical treatment that is 100% safe. Even putting on a band aid could have risk (you might be allergic to the adhesive). Essentially, it comes down risk versus benefit and both these change depending on the ailment being treated. For example, if you’re treating cancer, you would be prepared to endure a much higher risk treatment than if you had a cold. With a vaccine, you are treating a disease that the patient does not have. Therefore you could argue that there is no benefit to the patient so the risk has to be zero. But there is a benefit in preventing the disease if the patient is exposed and the public benefit of herd immunity is massive. Essentially, it is complicated.
The way that our society sees it is that vaccines do need to have very low risk and with a very short development and clinical trial length can that safety be guaranteed? The answer is both yes and no. We can comfortably prove short term safety, but can we guarantee long term safety. For example, the Dengue fever vaccination, where even after exhaustive trials and signing off from the WHO, it was found that vaccinated people were suffering from severe bouts of the disease. Essentially, they had vaccine enhanced disease. You can read more about it here:
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)32525-5/fulltext
It is also important to note that even with the cases of vaccine enhanced disease, the benefits to the community as a whole were extremely high as there was a marked decrease in deaths and hospitalisations. The other thing we have to be very concerned about is the fact that the Oxford vaccine is a live vaccine meaning that vaccine is actually a living virus. Now, we don’t need to stress too much, live vaccines have been used for ages. The first vaccines were live viruses including the smallpox vaccine which used the cowpox virus to give you immunity.
In any case, live vaccines need to be carefully monitored and scrutinised during the trial process as there is a small chance that the vaccine could cause disease. Live vaccines also provide an extra hurdle as people who are immunocompromised are advised against having live vaccines. This includes people with certain diseases (such as HIV), cancer patients, bone marrow transplant recipients, people who take steroids or other immune suppression or modulating drugs and the elderly. That’s a real problem as the people most vulnerable and liable to suffer from serious complications or death from COVID cannot be vaccinated. Yes, they will have to rely on herd immunity and realistically that all relies on at least 90% of the country being vaccinated. Approximately 22 million doses to everyone, including people that don’t want to get vaccinated. See the problem?
And then there’s efficacy. Some vaccines can be amazing. The smallpox vaccine offered life long immunity and was the main reason that smallpox was eradicated from the planet. However, other vaccines can only be partially effective or have a limited lifespan like the flu virus that only lasts six months. We simply don’t know how effective this vaccine is going to be. Even if the phase 3 trials prove efficacy, we will only know that it remains effective for a maximum of six months because that is how long the trial will have been active for.
In my next post, I'll wrap up my thoughts on vaccinations
Until next time,
Stay well:)
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