Doctor’s Note: Why will it take so long for a COVID-19 vaccine?

Scientists say it will take 12 to 18 months before a coronavirus vaccine can be ready. A doctor explains why this is.

The race is on to find a vaccine, but what is involved and how long will it take? [REUTERS/Andreas Gebert]
The race is on to find a vaccine, but what is involved and how long will it take? [REUTERS/Andreas Gebert]

Even with our best efforts at social distancing and self-isolating, there have still been more than one million people infected  with coronavirus and over 53,000 deaths worldwide.

Our long-term success in surviving and containing this pandemic will rely, in part, on the development of a vaccine against the virus.

There is now a global race to do this, with many different pharmaceutical and research institutes vying to be the first to create it. On March 20, 2020 the World Health Organization (WHO) stated that there are 44 COVID-19 vaccine candidates.  

But scientists say it will take around 12 to 18 months for a vaccine to be developed, approved and ready. 

How do vaccines work?

A vaccine works by presenting certain molecules – also known as antigens of the pathogen (the virus) – to the immune system. 

Traditionally these antigens are in a weakened or inactive form, so they cannot actually cause the illness. But our immune system is then able to recognise the antigen as an unwanted foreign invader, and forms antibodies, allowing it to “remember” the pathogen in case it tries to infect you in the future.

The antibodies you have built up will then attack the pathogen before it is able to make you unwell if you are exposed to it in the future.

Newer technology is now also allowing us to create a vaccine that is not made from the weakened or inactive pathogen at all, but instead from a copied genetic code from the virus, which is made in a laboratory. However, no vaccine that has been made in this novel way has been approved thus far. 

We have a head start

While United States President Donald Trump was optimistic in stating he thought a coronavirus vaccine would be available by November, most scientists would agree that it is more likely to take 12 to 18 months – and that is providing there are no bumps along the road. 

Some vaccinations can take up to a decade or more to be approved and licensed for use, so even producing a vaccine within 18 months would be a remarkable feat. 

One of the reasons that we may be able to achieve such a target is because COVID-19 is part of the coronavirus group, for which a lot of study and research has already been done. Previous pandemics involving coronaviruses include the severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) outbreaks. 

The groundwork for vaccinations for both these diseases was commenced during their outbreaks, but once the spread had been contained, this was then stopped.

Thanks to the genome sequencing of the new coronavirus provided by scientists in China, we know that the virus that causes COVID-19 disease shares 79 percent of the same genetic material as SARS, and 50 percent of the same material as MERS, so we do have a head start in creating a COVID-19 vaccine.

Trials for a vaccine

Most vaccine developers would do animal testing first before moving on to human trials.

There has been one new coronavirus trial in the US – the Moderna trial  – that has skipped the animal testing phase and gone straight to human testing in the hope that this might speed up the process of developing a vaccine.

However, even when animal testing is skipped, there are still several processes that need to be followed in human trials. The clinical development of a vaccine in human trials usually has three phases.

Phase one trials are small-scale to essentially assess whether the vaccine is safe in humans.

This phase usually involves around 100 participants. There is no set amount of time that each phase will take to complete, but typically the first phase takes several months. 

Phase two trials are larger, often involving several hundred subjects, and mainly evaluate the efficacy of the vaccine against the disease. This phase can last anything from several months to several years for many vaccines.

The final phase is on an even larger scale of thousands of people, often across several medical facilities. This phase also assesses the efficacy of the vaccine in fighting the disease over a defined period of time. This phase can last for anything up to a few years.

It is only after this final phase that the manufacturer may apply for a licence – from organisations such as the European Medicines Agency if the manufacturer is doing business in Europe – to market the vaccine. The research also undergoes a review by experts at this point.

The Moderna trial is currently still in the first phase, but is expected to reach the second stage around the middle of this year.

The development of the COVID-19 vaccine is being fast tracked as much as possible given the urgent demand for it. But even though we may already be at a stage where it has been manufactured and can undergo trials on humans, it is still likely to take 12 to 18 months before it is available worldwide for public health use, as safety cannot be compromised. 

Of course, the safety of the vaccine needs to be carefully balanced against the mortality and morbidity rates of the disease. 

This, however, is a new disease that we are still only starting to scratch the surface of, and more information is needed from further modelling and studies of the virus.

But it is not only the safety of a vaccine that is needed to roll out that vaccine: it also needs to be effective. What works in the lab may not work in the real world.

It is for this reason that both the safety and efficacy of a vaccine must be assessed through all phases of a trial, without cutting corners.

Source : Al Jazeera

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