COVID-19 vaccines were developed in a very short timeframe. How can we be sure that they are safe?
The process to develop and approve COVID-19 vaccines was accelerated while maintaining the highest standards. Manufacturers and researchers benefited from the experience acquired over decades with developing vaccines for other diseases, including Ebola. This made it possible to develop COVID-19 vaccines and fully evaluate them in clinical trials much faster than before.
Unprecedented investments made by governments and the private sector allowed the vaccines to be developed and produced in less than a year after the pandemic was announced.
How does the approval process for COVID-19 vaccines work?
Like all vaccines, COVID-19 vaccines go through a rigorous, multi-stage testing process, including large (phase III) trials that involve tens of thousands of people.
An external panel of experts convened by WHO analyzes the results from clinical trials, along with evidence on the disease, age groups affected, risk factors for disease, and other information. The panel recommends whether and how the vaccines should be used.
Once a clinical trial indicates that a COVID-19 vaccine is safe and effective, a series of independent reviews of the efficacy and safety evidence is required. Part of this process also involves a review of all the safety evidence by the Global Advisory Committee on Vaccine Safety.
How can we be sure that vaccines will not put us at risk in terms of side effects and severe adverse reactions?
Because the clinical trials took place in the middle of the pandemic with many people getting exposed, it was easier for clinical trials to see if the vaccines worked or not. These trials, which include some groups at high risk for COVID-19, were specifically designed to identify any common side effects or other safety concerns.
Side-effects from vaccines happen in the very first days after taking the vaccine. During the vaccine trials, follow-up of individuals included the time during which side-effects could have occurred, with a large margin to make sure al side effects were captured.
How do we know if the mRNA vaccines that are based on new technology are safe?
The COVID-19 mRNA vaccine technology has been rigorously assessed for safety. Clinical trials have indicated that mRNA vaccines provide a long-lasting immune response. mRNA vaccine technology has been studied for several decades, including in the contexts of Zika, rabies, and influenza vaccines. mRNA vaccines are not live virus vaccines and do not interfere with human DNA.
What does it mean when we say that a vaccine has been given emergency use authorization by WHO?
WHO works to ensure that everyone, everywhere is protected by safe and effective vaccines. To do this, we help countries set up rigorous safety systems for vaccines and apply strict international standards to regulate them.
Vaccines that are authorized for emergency use by WHO do so after going through an extensive review. This provides a stamp of quality, safety, efficacy, and manufacturing quality. To do that, we work closely with the European Medicines Agency and other national regulatory agencies.
Should everyone get vaccinated against COVID-19?
Yes, because vaccines prevent severe COVID-19 infection and death. Vaccination of large numbers of people is important if we want to get out of the current pandemic. Everyone should get vaccinated and encourage others to get vaccinated according to each country’s vaccination plan and recommended age limit for the vaccine. However, because there is not enough vaccine available early on, there is a prioritization scheme so that persons who need it the most can get the vaccine first.
Can someone vaccinated against COVID-19 still get infected?
While trials have indicated that several COVID-19 vaccines to have high levels of efficacy, like all other vaccines, COVID-19 vaccines are not 100% effective against the disease. However, if the disease occurs, the vaccine may be able to reduce the risk of severe illness or death.
We do not yet know how long immunity from different COVID-19 vaccines will last. That is one reason why we must continue using all public health measures that work, such as hand hygiene, physical distancing, masks, ventilation and cough etiquette.
What are the benefits of getting vaccinated?
COVID-19 vaccines produce protection against the disease by helping you develop an immune response to the SARS-Cov-2 virus. This immunity helps you fight the virus if exposed. Some COVID-19 vaccines are now reported as effective against the infection also.
Getting vaccinated may also protect people around you, because if you are protected from getting infected and from disease, you are less likely to infect someone else. This is particularly important to protect people at increased risk for severe illness from COVID-19, such as healthcare providers, older or elderly adults, and people with other medical conditions.
Do I need the vaccine if I have already had COVID-19?
The first question should be: did you have COVID-19 for sure? If the disease was not confirmed by a test, it’s hard to say. For people who had COVID-19 for sure, there are no reasons to exclude them from vaccination. However, in view of short supplies of vaccine it makes sense to prioritize people who did not have COVID-19 before. COVID-19 does give immunity for a few months.
What are the side effects of COVID-19 vaccines?
Like any vaccine, COVID-19 vaccines can cause mild side effects. Most reactions to vaccines are mild and go away within a few days on their own.
Reported side effects include fever, fatigue, headache, muscle pain, chills, diarrhoea, and pain at the injection site. The chances of any of these side effects following vaccination differ according to the specific COVID-19 vaccine.
More serious side effects to vaccines that can have long lasting consequence are possible but extremely rare. Vaccines are continually monitored to detect rare adverse events.
Should everyone get vaccinated against COVID-19?
Yes, because vaccines prevent severe COVID-19 infection and death. Vaccination of large numbers of people is important if we want to get out of the current pandemic. Everyone should get vaccinated and encourage others to get vaccinated according to each country’s vaccination plan and recommended age limit for the vaccine. However, because there is not enough vaccine available early on, there is a prioritization scheme so that persons who need it the most can get the vaccine first.
Medical professionals can best advise individuals on whether or not they should receive a COVID-19 vaccine. However, based on available evidence, people with the following health conditions should generally be excluded from COVID-19 vaccination to avoid possible adverse effects:
If you have a history of severe allergic reactions to any ingredients of the COVID-19 vaccine
If you are currently sick or experiencing symptoms of COVID-19, though you can get vaccinated once your primary symptoms have resolved.
