Doctor’s note: Why does it take so long for a COVID-19 vaccine? | Coronavirus pandemic


Even with our best efforts to distance ourselves and isolate ourselves, there have still been more one million people infected with a coronavirus and more than 53,000 deaths worldwide.

Our long-term success to survive and contain this pandemic will be based in part on the development of a vaccine against the virus.

There is now a worldwide race to do this, with many different pharmaceutical and research institutes competing for the first to create it. On March 20, 2020, the World Health Organization (WHO) declared that there are 44 COVID-19 candidate vaccines.

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


How do vaccines work?

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

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

Antibodies you have accumulated will then attack the pathogen before it can make you sick if you are exposed to it in the future.

Newer technology also allows us to create a vaccine that is not made at all from a weakened or inactive pathogen, but rather from a genetic code copied from the virus, which is made in the laboratory. However, no vaccine that has been manufactured in this new way has been approved so far.

We are one step ahead

While the President of the United States, Donald Trump, was optimistic when he said 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 means there are no bumps on the road.

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

One of the reasons why we could achieve such a goal is that COVID-19 is part of the coronavirus group, for which many studies and research have already been carried out. Previous pandemics involving coronaviruses include outbreaks of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

Preparatory work for vaccination against these two diseases started during their outbreaks, but once the spread was under control, it 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% of the same genetic material as SARS, and 50% of the same material as MERS, we so let’s have a an advance in the creation of a COVID-19 vaccine.

Vaccine trials

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

There has been a new coronavirus trial in the United States – the Moderna trial – who skipped the animal testing phase and went straight to human testing in the hope that it could speed up the process of developing a vaccine.

However, even when animal testing is ignored, several processes still need to be followed in human testing. The clinical development of a vaccine in human trials generally involves three phases.

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

This phase generally involves around a hundred participants. There is no set duration for each phase, but generally the first phase takes several months.

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

The final phase takes place on an even larger scale of thousands of people, often in several medical institutions. This phase also assesses the effectiveness of the vaccine in fighting the disease over a defined period of time. This phase can last up to a few years.

It is only after this final phase that the manufacturer can apply for a license – from organizations such as the European Medicines Agency if the manufacturer does business in Europe – to market the vaccine. The research also undergoes expert review at this stage.

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

The development of the COVID-19 vaccine is accelerated as much as possible given its urgent demand. But even though we may already be at the stage where it was manufactured and can be tested on humans, it will probably take 12 to 18 months before it is available worldwide for health purposes public because security cannot be compromised.

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

However, this is a new disease that we are just beginning to scratch the surface of, and more information is needed from other models and studies of the virus.

But it’s not only the safety of a vaccine that is needed to deploy it, it must also be effective. What works in the laboratory may not work in the real world.

It is for this reason that the safety and efficacy of a vaccine should be evaluated at all stages of a trial, without backing down.


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