Are the COVID-19 vaccines safe?

by Bram

By far most experts around the world agree and say:

“Take any approved COVID-19 vaccine that is offered to you, and take it as soon as possible”

  • How can the COVID-19 vaccines be developed so quickly?
  • Have any corners been cut?
  • Why don’t we need to worry about long-term side effects?
  • Is it safe?

Particularly for people with MS, an additional question is:

  • Why are experts almost certain that it won’t harm people with MS?

For our Dutch non-profit organisation ‘MS in beeld’ I created a webpage as well as a number of videos that discuss these topics in detail. Unfortunately, all this information is in Dutch. As people all around the world are asking these same questions, I decided to translate our webpage into English. Even though the background information that is available in the Dutch videos is lacking, I believe that this webpage can help you understand the safety of the vaccines.

How can the COVID-19 vaccines be developed so quickly?

Normally it takes much longer to develop a vaccine. Today, more than 500 million vaccinations have been given against COVID-19 within a single year. It seems that this could not have been done without cutting corners, or some kind of miracle.

Still, there are logical explanations for the rapid development, production and distribution of the vaccines.

Reason 1. Science has advanced

Usually, a research institute conducts research into a vaccine, e.g. a university or a research lab of a pharmaceutical company. All these research groups have learned a great deal in recent decades. Most labs already had a platform ready to develop a vaccine for the novel coronavirus.
Some labs were already making vaccines against SARS-CoV and MERS-CoV. Adapting the process to SARS-CoV2 (the name of the virus causing COVID-19) was relatively straightforward.

That is why some labs were able to start making prototypes almost immediately after Chinese researchers made the genetic code of the virus public.

Reason 2. Waste is accepted

An awful lot of money has been invested. That money was not used to bribe regulatory agents but to accelerate every step of development, approval, manufacturing, and distribution.

Normally experiments follow one another. Now they run side by side. Many experiments lead to nothing, but some do. This causes waste, but it leads to results much faster.

By the way, there is a will to invest because it is estimated that this pandemic costs the world about 500 billion dollars every month.

Reason 3. The regulatory agencies got to work immediately

Normally, the regulatory agencies like the FDA or EMA do not review vaccines or drugs until the phase I, II, and III studies have all been completed. Now they have already started their reviews during the studies. They call this a ‘rolling review’. This not only sped up the review process itself, but researchers were informed early if data was missing or additional data was required.

Reason 4. Mass manufacturing of the vaccine started early

After a safe and effective vaccine has been approved by the authorities, it still takes a long time to produce a large quantity of the shots.

With a normal vaccine, they only start manufacturing after a vaccine is approved. In this case, a lot of money has been invested to start manufacturing the vaccines even before they were approved, and even before the Phase III trials were completed. There is a risk that they will have to destroy large quantities of unsuccessful vaccines. However, with the hope that once a vaccine is approved, factories are up and ready, or perhaps even started production already.

Reason 5. Logistics have been prepared and plans were made advance

The distribution of the vaccine could already be thoroughly prepared. Countries often prepared a vaccination strategy in advance, built vaccination centers, and planned the rollout.

Have any corners been cut?

All medicines and vaccines are first tested in pre-clinical studies, i.e. studies with laboratory animals. Followed by clinical studies. These studies on humans are also called the ‘Phase’ studies. The same holds for the COVID-19 vaccines. The regulatory agencies are not allowed to cut corners. 

The video below by the BBC explains how a vaccine gets approved.

Why don’t we have to worry about long-term side effects?

A vaccine is different from a medicine that you take continuously. What is injected in the vaccines disintegrates and is cleaned up by our bodies within a few days. It does not divide, so the quantity is limited.

Experts cannot think of a reason and are almost certain that there will be no long-term side effects that have not manifested themselves within a few weeks after vaccination.
After thoroughly reviewing studies with vaccines in the past, the authorities have decided that it is sufficient for the Phase studies to follow subjects for at least six weeks. It is believed that possible side effects would have occurred within that time period.

This does not mean that vaccines cannot possibly cause any long-term problems, it means that these would have already been noticeable within six weeks after the vaccine was administered.

Experts agree that the study duration of at least six weeks has created a good picture of the side effects, including the rare ones. Although the vaccines are tested on tens of thousands of subjects in their Phase III trials, very rare side effects that did not occur in the study cannot be ruled out. Therefore, possible side effects of the vaccine are also closely monitored after approval -post-marketing surveillance-.

Is it safe?

More than 600 million vaccinations against COVID-19 have already been given worldwide and fortunately, the number of reported side effects is very low.
They are dwarfed by the risks that a COVID-19 infection itself entails. That is very important: the cure is in no way worse than the disease .

I imagine it like this, suppose that you gave 600 million people a free sample of M&M’s, then the number of reported side effects would have been far greater…

Why do experts agree that COVID-19 vaccines won’t harm people with MS?

The vaccines have not been specifically tested in people with MS. In Phase II and III clinical studies, the vaccine was tested on a large group of people, including dozens of people with MS.
Even though the pharmacists have not given specific results for people with MS, we know there were no strange side-effects that happened to people with MS in those studies. 

Experts also know from past studies 12 that there does not appear to be a link between vaccinations and MS relapses.

What can happen, is a so-called pseudo-relapse. This means that after vaccination your MS symptoms could temporarily be worse. That’s because your body is busy making an immune response to the vaccine. You can even develop a fever. That is normal. Fever can lead to a temporary increase of pre-existing symptoms. Fortunately, it does not trigger a relapse. This is also referred to as Uhthoff’s phenomenon. Fortunately, it will pass by itself and such a pseudo-relapse does not leave any lasting damage.
(Some people with MS also notice the same on a very hot summer’s day)

In England, some neurologists recommend that MS patients take Tylenol (paracetamol) after vaccination (1 gram every 4-6 hours up to 48 hours, if necessary). This can reduce discomfort and has no detrimental effect on the vaccination.

In MS it is important to keep in mind that infection with COVID-19 itself can lead to much worse outcomes. Your immune system can overreact because your body is overrun with viruses that divide at lightning speed. This can in rare cases be deadly, but in MS even a mild infection with COVID-19 might trigger a relapse.


Although at the moment a lot is not yet a 100% certain, this can be said with utmost certainty:

The likelihood of developing a COVID-19 infection that causes health issues
is far greater than
the health risks of an approved COVID-19 vaccine

And that’s the most important thing to know. Therefore, the advice of almost all experts is:

“Take any approved COVID-19 vaccine that is offered to you, and take it as soon as possible”

  1. Mailand, M. T. & Frederiksen, J. L. Vaccines and multiple sclerosis: a systematic review. Journal of Neurology 264, 1035–1050 (2017)
  2. Zrzavy, T. et al. Vaccination in Multiple Sclerosis: Friend or Foe? Frontiers in Immunology 10, (2019)

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More