It has been over a year since COVID-19 spread like wildfire across the globe. It brought with it seemingly never-ending lockdowns, economic crisis and complete disruption to our way of life. Scientific research and innovation have brought us the light at the end of the tunnel in the form of vaccines, the only way to fully get back to normal without fearing for the safety of our families every time we hug them. Thanks to the coordinated approach that every virologist, epidemiologist, pharmaceutical company and regulatory authorities across the world has had to the creation of the vaccines, they have been developed at a speed never before seen in a pandemic. This speed however has brought with it a sense of mistrust in the vaccine. Many wonder how it could have possibly been developed so quickly, and surely the speed of production has led to compromises on safety and testing. These fears are perfectly understandable, especially with only those of certain scientific disciplines having a full understanding of the entire drug development process and the safety tests and criteria that a drug must meet before it is administered to the public. The speedy development of the COVID-19 vaccines has caused many to doubt their safety and effectiveness. However, the COVID-19 vaccines are not the first vaccines that have had to be developed under emergency conditions and have been licenced on an emergency basis.
In 2018 during an outbreak of Ebola in Kivu, Africa, a vaccine for the deadly virus was created, called Ervebo, and despite not having gained full approval from the relevant regulatory authorities, 200,000 vaccines were administered to those in the affected regions. The vaccine was granted emergency approval, just like the Oxford-AstraZeneca vaccines were, because the regulators could see that the vaccine had passed all clinical safety and efficacy tests, and with no major issues flagging up during trials the benefit of the vaccine in ending the epidemic far outweighed the slight risks it could pose. This is indeed the case for all medicines, such as cancer medicines, which cause significant illness and toxicity in the patients, yet are still the first course of treatment as the benefits outweigh the risks.
The Ervebo vaccine had finished the development process in 2016, just as the 2014-2016 West Africa outbreak, which took the lives of over 11,000 people, came to an end. The vaccine, despite being almost ready to go was not used during this outbreak, because it had not begun the approval process, meaning that the government was not yet assured of its safety so did not administer it to the public. Despite not bring used during this outbreak and having not begun the full approval process yet, pharmaceutical companies began manufacturing doses in 2016, as they know that another outbreak was inevitable and they might be needed for emergency use. This is the same thing that happened with covid vaccines, with the manufacturers confident in the safety of their vaccine and its ability to be approved. Sure enough, the 2018 outbreak began and thankfully was brought to an end because 300,000 doses were administered to those at risk, having been granted emergency use approval. The vaccine was then fully licenced in 2019, as the emergency use had shown its safety in a larger number of people than could ever be involved in the clinical trials. This mirrors the administration of the Oxford-AstraZeneca COVID-19 vaccine, which when given to the millions of members of the public actually proved to be even more effective than originally thought, as the more people that receive the vaccine means the more accurate the efficacy values (how effective the vaccine is) are.
The main things holding back the Ebola vaccine efforts before the 2014 outbreak were the inability to demonstrate clinical efficacy (ie that it was working well) in the absence of an ongoing outbreak and a lack of interest by the public health and vaccine development community to invest in the lengthy and costly process of vaccine development without a clear demand for an Ebola vaccine. Again, this is a mirror image of the history of the covid-19 vaccine, which originated as a SARS (SARS-CoV1) vaccine model, and was able to be easily modified to work for COVID-19 (SARS-CoV-2) due to the two viruses being extremely similar, almost like virus ‘cousins’ (two very mischievous cousins at that). The development of a vaccine for coronaviruses began after the 2003 SARS pandemic, but development slowed once the pandemic had been contained. The SARS pandemic was not as devastating as the one we are currently experiencing, mainly because although SARS and COVID-19 are very similar, SARS is not as transmissible as COVID-19, and therefore it was able to be contained through classical non-pharmaceutical interventions, such as contact tracing, testing, and quarantine. As the pandemic has proved, COVID-19 is far more difficult to contain this way, due to its high transmissibility and high proportion of asymptomatic cases, therefore the vaccines are needed if we want this pandemic to truly end and life to go back to normal.
The Ervebo vaccine, like the Oxford COVID-19 vaccine is a recombinant, live, replication-disabled vaccine. This means that the vaccine contains a version of the virus itself that has been genetically modified to remove the genes that allow the virus to replicate. This means that the virus will not be able to replicate inside us, but will still be able to be seen, remembered, and destroyed by our immune system’s. This type of vaccine takes the longest to get approved, because it must be thoroughly checked to make sure the virus truly is replication-disabled (can’t work), which explains why the Pfizer-BioNTech vaccine (not a live vaccine) was the first of the COVID-19 vaccines to be approved.
The purpose of this post is to highlight to you, dear readers, that sometimes vaccines have to be licenced on an emergency basis. Despite this, there are never any compromises made to testing and safety. The development of the Ervebo vaccine is a perfect example of this. If the Ebola vaccine had not been ready to give to the people that needed it when they needed it, the 2018 Kivu outbreak could well still be ongoing. It could also have spread to other parts of Africa, and even beyond. We have enough on our plate at the moment without risks like that!
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