Vaccine safety

Coronavirus disease (Covid-19):
Vaccine safety
19 February 2021
 Q&A

How do we know that Covid-19 vaccines are safe?
Strict protection measures have been put in place to help ensure the safety of all COVID-19 vaccines.
Before Covid-19 vaccines obtain accreditation from the World Health Organization and national regulatory agencies, they must undergo rigorous testing as part of clinical trials to demonstrate that they meet internationally agreed standards of safety and efficacy.
The unprecedented scientific collaboration has enabled research on COVID-19 vaccines to be completed, developed, and permits issued for their use in record time - with the aim of meeting the urgent need for Covid-19 vaccines, while maintaining high-level safety standards. As with all vaccines, WHO and regulatory authorities will continually monitor the use of COVID-19 vaccines to ensure that they are still safe for everyone who receives them.



What are the side effects of Covid-19 vaccines?
Covid-19 vaccines, like any other vaccine, can cause mild side effects, such as a mild fever, or pain or redness at the injection site. Most reactions to vaccines are mild and disappear on their own within a few days.
Vaccines can have more serious or long-term side effects, but these are very rare cases.
Vaccines are constantly monitored to detect any rare adverse events.
The side effects of the Covid-19 vaccines that were reported range from mild to moderate, as well as short-term, and include the following symptoms: fever, fatigue, headache, muscle pain, chills, diarrhea, and pain at the injection site.
The chances of any of these side effects occurring after receiving the vaccination vary according to the type of Covid-19 vaccine given.



What is the relationship between Covid-19 vaccines and allergic reactions?
WHO is aware of reports of severe allergic reactions in a small number of people who have received the Covid-19 vaccine.
A severe allergic reaction -such as anaphylaxis- is a possible side effect but is rare with all vaccines.
For people at known risk, such as previous cases of an allergic reaction to a dose of vaccine or any known vaccine component, precautions may be required.
The organization recommends that health care providers evaluate a patient's medical history to find out if the patient is at risk of a severe allergic reaction to Covid-19 vaccines.
All immunization service providers should be trained to recognize severe allergic reactions and take practical steps to treat such reactions if they occur.
National authorities and international bodies, including the World Health Organization, will closely monitor the use of Covid-19 vaccines, with the aim of detecting dangerous side effects, including any unexpected side effects.
This will help us better understand and manage the specific risks of allergic reactions or other serious side effects of Covid-19 vaccines that may not be detected during clinical trials, ensuring a safe vaccination for all.



What happens if I report an adverse event?
It is imperative that the safety and effectiveness of COVID-19 vaccines are closely monitored when they are administered, as is the case with any other vaccine. If a problem is reported following vaccination, a thorough investigation should be undertaken.
During these investigations, it is extremely rare to discover health problems caused by the vaccine itself.
Often the adverse events turn out to be a coincidence and may not have anything to do with vaccination.
Sometimes, these accidents are related to how the vaccine was stored, transported, or administered.
These mistakes can be avoided by improving health worker training and strengthening supply chains.
In the very rare cases where a true adverse reaction is suspected, the use of the vaccine may be suspended.
Additional investigations will be conducted to find out the exact cause of the accident, and corrective measures will be taken accordingly.
WHO is working with vaccine manufacturers, health officials and other partners to continuously monitor any safety concerns and any potential side effects.



Under what circumstances should a Covid-19 vaccine be withdrawn?
Rarely, a vaccine is withdrawn for safety reasons.
Usually, the vaccine manufacturer voluntarily withdraws the vaccine before any adverse events are reported.
For example, continuous monitoring of vaccine production may show that a breach has caused a batch of vaccines to lose their potency.
In this case, people who were vaccinated from that batch may need to be vaccinated again to ensure that they are protected.



How will WHO notify the public of suspected or confirmed adverse incidents caused by COVID-19 vaccines?
Medical professionals can best advise individuals on whether or not they should receive the COVID-19 vaccine.
However, based on the available evidence, people with the following health conditions should generally be excluded from the COVID-19 vaccination in order to avoid potential adverse effects:
    If you have previously had a severe allergic reaction to any component of the Covid-19 vaccine
    If you are sick or are currently showing symptoms of Covid-19, but you can receive the vaccination as soon as the initial symptoms of the disease have passed.
More research is needed to determine the safety and effectiveness of various COVID-19 vaccines in specific populations.
In addition to the general recommendations mentioned above, specific considerations according to population group and morbidity may be applied to each vaccine.
Suspected safety incidents that are formally reported to WHO are subject to a series of rapid verification procedures involving an independent team of experts.
The organization publishes the results of these assessments on its website.
WHO is also coordinating with local, regional and national health officials to discuss vaccine safety concerns and provide advice.
Regarding the next steps.
Information is also made available via the Vaccine Safety Network, a network of international, publicly available digital resources on the safety of vaccines approved by WHO.



Can a person who received the COVID-19 vaccination get infected?
Although many Covid-19 vaccines appear to have high levels of effectiveness, no vaccine will protect against the disease 100%.
As a result, a small percentage of people may not have the expected protection after receiving the COVID-19 vaccination.
In addition to the specific characteristics of the vaccine, there are many factors that can affect the effectiveness of the vaccine, such as a person’s age, underlying health impairment, or previous exposure to Covid-19 infection.
Also, we do not yet know how long it will take to acquire the acquired immunity from the various Covid-19 vaccines.
This is among the reasons that oblige us to continue applying all public health measures that have proven effective, such as physical distancing, wearing masks, and washing hands, even in the context of the start of the introduction of Covid-19 vaccines.



What groups should not receive COVID-19 vaccines?
Medical professionals can best advise individuals on whether or not they should receive the COVID-19 vaccine.
However, based on the available evidence, people with the following health conditions should generally be excluded from the COVID-19 vaccination in order to avoid potential adverse effects:
    If you have previously had a severe allergic reaction to any component of the Covid-19 vaccine
    If you are sick or are currently showing symptoms of Covid-19, but you can receive the vaccination as soon as the initial symptoms of the disease have passed.
More research is needed to determine the safety and effectiveness of various COVID-19 vaccines in specific populations.
In addition to the general recommendations mentioned above, specific considerations according to population group and morbidity may be applied to each vaccine.



Is it safe for pregnant women, women intending to become pregnant and breastfeeding mothers, to receive COVID-19 vaccines?
Based on our knowledge of these vaccines, there is no specific reason to believe that the risks of vaccinating pregnant women will outweigh the benefits.
While pregnancy increases women's risk of severe disease caused by COVID-19, very little data is available to assess the safety of vaccines during pregnancy.
For this reason, pregnant women who are at high risk of infection with SARS-CoV-2 (such as health workers) or who have comorbidities that increase their risk of severe disease can be vaccinated after consulting with their health care provider.
It is not clear whether Covid-19 vaccines can be excreted in breast milk during breastfeeding.
To determine the best course of action, consideration should be given to the benefits of breastfeeding for development and health, along with the mother's clinical need for immunization against COVID-19.
The organization does not recommend stopping breastfeeding after receiving vaccination.



Are messenger RNA vaccines safe? How can we be sure of its safety if it is based on a new technology?
The technology of mRNA Covid-19 vaccines has been carefully evaluated to ensure its safety, and clinical trials have shown that mRNA vaccines generate a long-term immune response.
This technology has been studied for several decades, including in vaccine contexts against Zika virus, rabies and influenza.
And mRNA vaccines are not vaccines made with live viruses and do not interfere with human DNA.



How will WHO ensure that vaccine safety and response are monitored when using COVID-19 vaccines?
Vaccine safety monitoring is ensured at the national, regional and global levels.
In accordance with standard practice in all national immunization programs, WHO supports the establishment of systems to monitor the safety of COVID-19 vaccines in each country.
After the COVID-19 vaccine is introduced in a country, WHO is working with vaccine manufacturers, health officials and other partners to track any safety concerns and any potential side effects on a continuous basis.
WHO and an independent team of experts (the Global Advisory Committee on Vaccine Safety (GACVS)) will assess safety concerns in cooperation with relevant national authorities.

The Source:
https://www.who.int/ar/news-room/q-a-detail/coronavirus-disease-(covid-19)-vaccines-safety