The scale of impact of Covid-19 on the world’s health and economy is only now becoming evident. It seems likely that the number of cases is likely to exceed three million and the number of deaths may exceed 300,000. The genetic sequence of the Coronavirus that causes Covid-19 was published in January and this discovery stimulated a worldwide drive to develop a vaccine against the disease. There are more than 120 projects seeking to develop a vaccine for this new viral pandemic. The advantage of this “many irons in the fire” approach is that it will assist the identification of the best vaccines possible and will off-set the risk of failure of some of the vaccine development projects. The diversity of outcomes from the large number of projects may also assist the identification of vaccines for targeted populations of vulnerable patients such as older patients.
Some viruses mutate or change their genetic character very rapidly (such as common flu), which requires an annual adjustment of the genetic mix to remain effective against a constantly changing target. This is the reason that people need to have flu vaccinations every year. On the other hand, measles virus mutates very slowly so a patient may only require one or two vaccinations in a lifetime. The rate of mutation of Covid-19 is still being explored but there is hope that the rate is not too fast so a single vaccine shot may serve for many years.
Clinical trials are essential for new vaccines to ensure that they are not toxic, exhibit the necessary immune response in animals, work well with small groups of humans and then in larger groups of humans (perhaps thousands). These stages of clinical trials of vaccines normally take years to complete and are expensive to run. For the prospective Covid-19 vaccine, a further time-consuming challenge is the manufacturing scale-up of the production from laboratory levels to national or global supply levels. In a current Oxford University Covid-19 vaccine development project, the researchers and the university are taking a financial risk by developing the vaccine and the manufacturing aspects in parallel. If the vaccine fails in its development or trial stages, the investment in a manufacturing process will be an expensive failure. Another barrier is gaining regulatory approval for a vaccines deployment globally. This involves clearance by international agencies like the Food and Drug Administration (FDA) and the USA Environmental Protection Agency (EPA) that provide the ultimate consumer protection for new drugs and vaccines. The FDA and other agencies have indicated, given the global threat from Covid-19, that they would fast-track the review of this new vaccine.
The world will have an effective vaccine to combat the catastrophic impact of Covid-19 but this will take some time. Despite the fast-tracking of the development, manufacturing, regulatory clearance and distribution, this end-game for Covid-19 is not likely to happen until next year.