Recently there has been a lot of talk about Covid-19 vaccines in the media. Some countries have already started vaccinating, while most are still waiting. Many people have doubts about the vaccines seeing as they have been made so fast, and even people who are usually pro vaccine are considering not taking it when it becomes available. So in this article, lets take a look at what is actually going on with the vaccines.
The vaccines
Currently, there are over 100 potential Covid vaccines under development, and about 58 of these have reached the last stage: human trials. 7 of these have been approved for early or limited use, but none have yet been approved for full use.
Normally, vaccines require many years of research and testing before they are approved for regular use, but with Covid, the case has been a bit different. It usually takes about 10 years from the idea to it being made available to consumers, but in this case, it is expected to be about two years. However, it is possible to get a conditional authorization for a vaccine, meaning it can be approved before long-term data on effects and possible side effects are available, if the benefits of a vaccine outweighs the risks. The manufacturers then have to submit their data to health officials for assessment as soon as it becomes available.
One of the things that normally slows down the development process a lot is funding. It can take many years to get enough funds to be able to develop and test a vaccine, but with Covid vaccines it has been easy since millions and millions have been poured into the project by various donors.
From lab to clinic
Once scientist think they have a possible vaccine, it has to go through a lot of tests before it can be approved for regular use.
First, there is a preclinical test where the potential vaccine is first tested on cells and afterwards on animals like mice or monkeys. This is done to see if the vaccine produces an immune response.
Once this has proved a success, the vaccine enters the phase 1 safety trials. Here it is given to a small number of people to test the safety of it as well as how large the dosage should be - and to confirm it actually stimulates the immune system in humans.
In phase 2, the vaccine enters into expanded trials. The vaccine is given to hundreds of people split into demographic groups to see if the vaccine acts differently in different people. This is also a further test of safety and the ability to stimulate the immune system.
Finally, the vaccine enters phase 3. This is an efficiency trial, where the vaccine is given to thousands of people. Scientists then wait and see how many become infected compared to volunteers who received a placebo. It is in this stage that it can be properly determined if a vaccine properly works. Phase 3 trials are also large enough to reveal relatively rare side effects that might be missed in earlier tests.
After phase 3, regulators in each country review the trial results and decide whether or not they want to approve the vaccine. If worrying symptoms have been observed, the trial can be put on pause. After a further investigation, the trial will then either be resumed or abandoned. It is also possible to speed the test process up a bit by combining phases, and this is being done with some of the potential coronavirus vaccines.
During pandemics, it is possible to authorize emergency use of a vaccine before it is formally approved. This has so far been done in China, Russia and the UK. Especially the Russian approval has been criticized internationally since they approved the vaccine before it had even entered the phase 3 trials.
Covid Vaccines
Vaccines work by preparing the body's immune system to recognize and fight off the virus they target. If the body has already been introduced to the germs that cause the disease, the body is much more efficient in fighting it at a later time.
There are multiple different ways of getting the body familiar with the virus in a safe way, and this reflects in the types of vaccines in development. Genetic vaccines deliver one or more of the virus's own genes into our cells to provoke a response from the immune system. This is the way some of the most popular vaccine candidates like Pfizer/BioNTech that has been authorized for limited use in the UK does it. Another type is Viral Vector vaccines that contain viruses engineered to carry coronavirus genes and causing cells to produce viral proteins. This is the type that has been approved for early use in both China and Russia. Still other types of vaccines contain coronavirus proteins but no genetic material, or are created from weakened coronaviruses. Some of the last type has been approved for limited use in China and the United Arab Emirates.
However, none of the vaccines that has announced a high efficiency in its phase 3 results have published the latest findings in a peer-reviewed scientific journal yet, meaning the results are potentially questionable.
Distribution and safety
Even though the corona vaccine trials have happened much faster than usual, the important trial steps have been made. There will also continue to be made checkups on the vaccinated people to make sure there are no further side effects or longterm risks by taking it.
One important thing that hasn't been determined in the tests yet is whether the vaccines reduce spreading of the virus, meaning in the worst-case scenario, people who are vaccinated could still get an asymptomatic infection and transmit that to others. This however is still being tested and studied.
It is also not yet known how long the immunity provided by the vaccines will last. That will have to be monitored further by public health officials.
There hasn't yet been enough data for any of the vaccines to indicate how well they do in different age groups, or in people who are pregnant or obese. That will most likely require real-world data from large numbers of vaccinated people before it is possible to determine if there are certain groups that aren't as well protected by the vaccines as other are.
In the question of which vaccine countries will end up using, distribution might end up playing an important role, especially in the case of how the vaccine has to be stored. For example, the Pfizer vaccine that the UK has approved has to be stored at -70 degrees Celsius, which can be a real problem if it needs to be transported far. Other potential vaccines doesn't have the same requirements.
But, at the end of the line, it looks like there are many possible vaccines that seem about equally good - and it has been estimated that vaccines should start becoming available for the most vulnerable groups in many countries in the beginning of 2021.
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