Safety of COVID-19 Vaccines

The severe adverse events that may happen after vaccination

Mariam Alikhanova
V for vaccination- women shows that she just got her vaccine against COVID-19.
UNICEF Armenia/2021/Galstyan
17 May 2022

What You Need to Know:

  • COVID-19 vaccines are safe and effective.
  • Millions of people around the world and including in Armenia have received COVID-19 vaccines and been monitored.
  • It is important to receive the COVID-19 vaccine and the booster dose as soon as possible following the RA Ministry of Health’s timeline guidance.
  • The benefits of COVID-19 vaccination continue to outweigh any potential risks.

Hundreds of millions of people have safely received a COVID-19 vaccine

More than 11 billion COVID-19 vaccinations have been administered worldwide since the launch of COVID-19 vaccination, including more than 2․1 million in Armenia starting from 13 April, 2021.

COVID-19 vaccines are safe and effective. COVID-19 vaccines were evaluated in tens of thousands of participants in clinical trials. The vaccines met WHO’s, USA’s Food and Drug Administration’s (FDA) and other rigorous scientific standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization. 

All COVID-19 vaccines approved for emergency use by WHO continue to undergo the intensive safety monitoring. This monitoring includes using both established and new safety monitoring systems to make sure that COVID-19 vaccines are safe.

Common Side Effects

Some people have no side effects after any type of vaccination. Others have reported side effects, such as headache, fatigue, and soreness at the injection site, that are generally mild to moderate and go away within a few days. Side effects may affect the ability to do daily activities, but they should go away within a few days. Learn more about common side effects after COVID-19 vaccination.

Serious Safety Problems Are Rare

In rare cases, people may experience serious health events after COVID-19 or any other type of vaccination. Any health problem that happens after vaccination is considered an adverse event. An adverse event can be caused by the vaccine or can be caused by a coincidental event not related to the vaccine, such as an unrelated fever, that happened following vaccination. All medical products, including commonly used medicines like paracetamol and ibuprofen, are tested for safety but may still have unexpected side effects. The same is true for COVID-19 vaccines.

To date, the systems in place to monitor the safety of these vaccines have found four serious types of adverse events following COVID-19 vaccination, with evidence that suggests, although rare, a link to certain types of COVID-19 vaccines that were administered.

The following severe adverse events after COVID-19 vaccination have been registered:


Anaphylaxis is a severe type of allergic reaction that can occur after any kind of vaccination with symptoms such as hives, difficulty breathing, low blood pressure, or significant swelling of the tongue or lips. Anaphylaxis after COVID-19 vaccination is rare. According to US studies it has occurred at a rate of approximately 5 cases per one million vaccine doses administered. In Armenia it has occurred at a rate of approximately 3.2 cases per one million vaccine doses administered /2,183,124 doses administered and 7 cases of Anaphylaxis/. If it happens, healthcare providers can effectively and immediately treat the reaction. Learn more about possible allergic reactions following COVID-19 vaccination.

Thrombosis with Thrombocytopenia Syndrome (TTS)

Thrombosis with thrombocytopenia syndrome (TTS) is a rare but serious adverse event that causes blood clots or issues with clotting in large blood vessels and low platelets (blood cells that help form clots). TTS after COVID-19 vaccination is rare. According to US studies, it has occurred in approximately 4 cases per one million doses administered. In Armenia only 1 case of TTS has been registered out of more than 2 million doses administered. A review of reports indicates a causal relationship between several COVID-19 vaccines and TTS.

However, the risk of a blood clot from COVID-19 disease is much higher than from COVID-19 vaccines.

If you have any of the following symptoms within 30 days of vaccination, contact your doctor immediately:

  • severe headache or blurred vision
  • chest or abdominal pain
  • vomiting
  • leg swelling or unusual skin bruising
  • difficulty breathing

Myocarditis and Pericarditis

Myocarditis is inflammation of the heart muscle, and pericarditis is inflammation of the outer lining of the heart. Most cases have been reported after receiving mRNA COVID-19 vaccines, particularly in male adolescents and young adults. Most patients with myocarditis or pericarditis after COVID-19 vaccination respond well to medicine and rest, and felt better quickly. Myocarditis and pericarditis after COVID-19 vaccination are rare. In Armenia, no cases of myocarditis or pericarditis have been reported.

The symptoms of very rare cases of myocarditis and pericarditis following vaccination with mRNA COVID-19 vaccines are:

  • new and persisting chest pain
  • shortness of breath
  • racing/pounding heartbeat

If you experience these symptoms within a few days of vaccination, contact your doctor immediately.

Guillain-Barré Syndrome (GBS)

Guillain-Barré Syndrome (GBS) is a rare disorder where the body’s immune system accidentally attacks the nerves coming out of the spinal cord, causing muscle weakness and sometimes paralysis. Anyone can develop GBS, but people older than 50 are at greatest risk. Most people affected recover fully. GBS after COVID-19 vaccination is rare. In Armenia no vaccine related cases of GBS have been registered.

There have been very rare reports of cases of Guillain-Barré Syndrome after vaccination with some COVID-19 vaccines. It is not yet known whether these cases are connected to or caused by the vaccines. Guillain-Barré Syndrome has many causes, including COVID-19 disease itself.

If you experience any of these symptoms within 42 days of vaccination, contact your doctor immediately:

  • Weakness or tingling
  • Double vision
  • Difficulty breathing, speaking, chewing, or swallowing
  • Difficulty walking
  • Loss of bladder or bowel control

Reports of Death Are Rare

Reports of death after COVID-19 vaccination are rare. Reports of adverse events to following vaccination, including deaths, do not necessarily mean that a vaccine caused a health problem. In Armenia, post-vaccination deaths were not causally related to vaccination.

Benefits of Vaccination Outweigh the Risks

Serious side effects that could cause a long-term health problem are extremely unusual following any vaccination, including COVID-19 vaccination. The benefits of COVID-19 vaccination outweigh the known and potential risks.

This article is made possible by the generous support of the American people through the United States Agency for International Development (USAID). The contents are the responsibility of authors and do not necessarily reflect the views of USAID or the United States Government.