How close are we to a coronavirus vaccine?

As part of our ‘Life & Health – Quick Read’ series, Dr. Achim Regenauer shares his insights and personal opinion on the timing of a coronavirus vaccine.

Until a few years ago, it would have taken 15 to 20 years to develop and roll out a new vaccine against a new infectious disease. More recently, Ebola took just 5 years. With COVID-19 holding social and economic life so tightly in its grip, the pressure is on for a SARS-CoV-2 vaccine within 12 to 18 months (i.e. latest mid-2021). But is that realistic? What could enable such an acceleration?

Examples of minimum years taken for vaccine development. Source: Plotkin’s Vaccines (7th Edition).

In contrast to SARS-CoV-1 in 2003 (SARS) which took several months, researchers sequenced the genome of SARS-CoV-2 within a few weeks of the first outbreak. Genome sequencing is key to understanding what’s going on inside and on the surface of the virus at the molecular level, giving an insight into which parts cause immune reactions.

Another way to expedite the vaccine development process is to put as many candidates in the race as possible: more than 150 vaccine candidates against SARS-CoV-2 are currently in development. This is exceptionally high.

Rather than time-consuming egg- and cell-based platforms, as previously used for influenza vaccines, new development-and-manufacturing platforms that can better target pathogens are now increasingly being used and developed. Gene-based platforms (DNA and RNA) are amongst those with the greatest potential for speed, although none of these have as yet resulted in an approved vaccine.

Given the high bar of delivering a drug that can be administered to healthy individuals and the typically high failure rate of vaccine candidates (up to 90%), pharmaceutical companies generally instigate multiple candidates, for each following a linear sequence of separate trials, e.g. for safety, efficacy and dosing, with numerous checks in between. Given the immense pressure for a SARS-CoV-2 vaccine, less such trials are being run, and trials are being run simultaneously rather than one after the other, potentially condensing years of development into months.

A lot of questions have to be answered by these trials: For example, does a vaccinated patient develop antibodies? How many? Are they the right kind of antibody to neutralize the virus? Will a single-dose vaccine confer immunity? How long will it last? Does the vaccine even backfire our immune system in the way that it even enhances a SARS-CoV-2 infection to a severe form of COVID-19? Running the trials simultaneously is more time-efficient, but learnings from one stage can’t direct another, the effect of that has yet to be seen.

If a vaccine is found, approval could be accelerated via the issue of an emergency-use provision so that, for example, highly exposed healthcare workers can be vaccinated. The next big challenge will then be to quickly manufacture billions of vaccine doses. The infrastructure needed for this differs depending on the vaccine type. If more than one vaccine is approved, these could be independently manufactured in different countries and production facilities. Some pharmaceutical companies and global foundations have already started advance-building vaccine manufacturing facilities, at their own risk.

Despite the challenges, the chance of a SARS-CoV-2 vaccine by mid-2021 is in my opinion likely. What’s more, the knowledge and technological advances happening now in immunology and vaccine development will put us in a better position to deal with future new pandemic diseases. The next major question, however, will be how long the vaccination protects against SARS-CoV-2 infection; looking at the duration of immunity against other coronaviruses, it may only protect for a few years.