It is a myth that the COVID-19 vaccine weakens the immune system. After someone receives a vaccine, their immune system is better equipped to protect against subsequent infections.

Although there are slight differences in the ways that the various COVID-19 vaccines work, they all follow the same principle. They help the body create immunity, or resistance, to SARS-CoV-2 — the virus that causes COVID-19 — by mimicking an infection. The immune system then remembers how to fight that infection in the future.

COVID-19 vaccines strengthen and prime the body’s immune response and help prevent serious COVID-19 disease and hospitalization.

Some European regulators have expressed concerns that giving COVID-19 booster shots too frequently could weaken the immune response to the vaccination. However, this is not the same as weakening a person’s immune system overall.

Read on to learn more about how the vaccine affects the immune system.

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All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub for the most recent information on COVID-19.

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COVID-19 vaccines contain information about SARS-CoV-2. Depending on the type of vaccine, it may contain either harmless pieces of the virus or its genetic material. The vaccine does not transmit COVID-19 because it does not contain the whole virus.

When the vaccine enters the body, it enters the cells. The body’s cells produce the virus spike protein, which mimics an actual SARS-CoV-2 infection.

The body has specialist white blood cells called helper T cells circulating in the blood, patrolling for invaders. When they detect virus spike proteins, they alert the immune system. The resulting immune response involves B cells that create antibodies to mark the spike protein for destruction.

Additionally, B cells stop the virus from entering cells. The vaccine also alerts killer T cells to destroy any infected cells. This coordinated response creates immunity or resistance in the body against SARS-CoV-2.

The T cells and B cells both remain in the body and can provide long lasting protection against COVID-19.

No, the body’s immune system is not weakened after a person gets a COVID-19 vaccine. The vaccine affects the immune system by preparing it to fight SARS-CoV-2.

Healthcare workers have administered millions of doses of vaccines to people of all ages, and data shows they are extremely effective in preventing severe COVID-19 disease. If someone had a weakened immune system following COVID-19 vaccination, they would have a more severe disease — but this is not the case.

The vast majority of individuals needing hospitalization for COVID-19 are unvaccinated.

However, there have been concerns from some European regulators that giving COVID-19 booster shots too frequently could weaken the immune response to the vaccination. This is not the same as weakening a person’s immune system overall.

Regulators argued against booster doses every 3–4 months, saying that overloading the immune system with repeated immunization could dampen the response. The immune system may need time to process the information from initial vaccinations to respond optimally to boosters.

However, at present, there is limited data on this topic.

The Centers for Disease Control and Prevention (CDC) currently recommend that everyone over age 5 years have a booster at least 2 months after their initial shots. Experts know that vaccination is the best way to protect against severe disease and death, so all people who are able should be vaccinated.

Vaccines undergo years of testing before they are authorized for use, and officials constantly monitor them for safety and efficacy. However, there are many myths and misconceptions about COVID-19 vaccines that can cloud accurate information about how they work and their safety.

Here are some of the most common ones:

  • Vaccine ingredients are dangerous: No, they are not. COVID-19 vaccines do not contain aborted fetal cells, drugs, or metals. Their ingredients also appear on many food labels, such as fats, sugars, and salts.
  • Natural immunity is superior: No, it is not. COVID-19 vaccinations are safer and more effective than natural immunity, which can come with serious risks and side effects.
  • The vaccines contain microchips: No, they do not. They help fight disease and cannot track a person’s movements.
  • COVID-19 vaccines cause COVID-19 disease: No, they do not. As they do not contain the whole virus, they cannot cause disease.

Having the COVID-19 vaccination helps protect individuals and communities against COVID-19 disease. It reduces the number of people who get sick, prevents hospitalizations, and saves lives. The more people vaccinated, the greater the protection for everyone.

By having the vaccination, people reduce the risk of potentially severe and life threatening illness and post-COVID conditions. So-called “long COVID” can cause fatigue, anxiety, brain fog, and other symptoms that can last for weeks or even months.

COVID-19 vaccination also helps protect healthcare workers and other essential workers who cannot socially distance themselves. Vaccination is a key tool to help return society to some degree of normalcy.

Everyone who is able should get the vaccine. The CDC recommends that all individuals over 6 months old get vaccinated. This includes most people with underlying health conditions and those who are immunocompromised.

It is also safe for pregnant and nursing individuals to get the vaccine. There is no evidence that the vaccine causes harm to either the mother or the developing fetus.

There are very few medical reasons why a person should not get the COVID-19 vaccine. If a person has any doubts or concerns about getting vaccinated, they should speak with a healthcare professional.

Read more about medical exemptions for the COVID-19 vaccine.

COVID-19 vaccination is a key tool in the fight against the disease. It is safe and effective for people of all ages, including pregnant and nursing individuals.

There is no evidence that COVID-19 vaccines weaken the immune system or cause long-term side effects. On the contrary, they help protect people from a potentially severe and life threatening illness. Vaccination both protects the individual and helps reduce the spread of disease to those who are most vulnerable.