Are the vaccines safe? (Updated*)

Are the vaccines safe?

To be administered in the United States, a COVID-19 vaccines needs an emergency use authorization by the FDA, and their approval process also includes public and independent review from members of the agency’s Vaccines and Related Biological Products Advisory Committee.  Adverse events are being tracked and all participants are asked to report side effects through the CDC V-safe smartphone tool.  Vaccine providers are required to report vaccine-related adverse events to the Vaccine Adverse Event Reporting System (VAERS).

Pfizer-BioNTech and Moderna

Because it is not a live vaccine, you cannot get COVID-19 from the mRNA vaccines. Also, they do not enter the nucleus of the cell and therefore cannot alter your genes. During the trials, there were no reported serious side effects from these two vaccines. Since becoming available to the first priority groups, there have been rare reports of allergic reactions/other serious adverse events with millions of doses given.

Johnson & Johnson

The Johnson and Johnson (Janssen) vaccine is a one dose, adenovirus-based vaccine.  Researchers genetically altered a weakened version of a common cold virus (adenovirus) that causes infections in so it carried a gene for the COVID-19 spike protein; this will train a person’s immune system to recognize the real coronavirus.  You cannot get COVID-19 from this vaccine.

Guillain-Barre Syndrome

On July 13, the FDA announced revisions to the fact sheets for the Johnson & Johnson COVID-19 Vaccine to include information pertaining to an observed increased risk of Guillain-Barré Syndrome (GBS) following vaccination. GBS is a neurological disorder in which the body’s immune system damages nerve cells, causing muscle weakness, or in the most severe cases, paralysis. Based on an analysis of Vaccine Adverse Event Reporting (VAERS) data, there have been 100 preliminary reports of GBS following vaccination with the Janssen vaccine after approximately 12.5 million doses administered. Of these reports, 95 of them were serious and required hospitalization. There was one reported death. Each year in the United States, an estimated 3,000 to 6,000 people develop GBS. Most people fully recover from the disorder. GBS has also been observed at an increased rate associated with certain vaccines, including certain seasonal influenza vaccines and a vaccine to prevent shingles.  Although the available evidence suggests an association between the Janssen vaccine and increased risk of GBS, it is insufficient to establish a causal relationship. No similar signal has been identified with the Moderna and Pfizer-BioNTech COVID-19 vaccines.

Thrombocytopenia Syndrome

The FDA has added a warning to the EUA fact sheets/prescribing information which notes that blood clots involving blood vessels in the brain, abdomen, and legs along with low levels of platelets have occurred in some people who received the Janssen COVID-19 vaccine and that these symptoms began approximately 1-2 weeks following vaccination. Most people who developed these blood clots were women ages 18-49 years.  Although the chance of having this occur is remote, people should seek medical attention right away if they have any of the following symptoms after receiving Janssen COVID-19 vaccine:

  • Shortness of breath
  • Chest pain
  • Leg swelling
  • Persistent abdominal pain
  • Severe or persistent headaches or blurred vision
  • Easy bruising or tiny blood spots under the skin beyond the site of the injection.

ACIP reviewed a risk-benefit assessment of thrombosis with thrombocytopenia syndrome (TTS) events after vaccination with the Janssen COVID-19 vaccine. Based on this risk-benefit analysis, ACIP reaffirmed its interim recommendation for the use of the Johnson & Johnson vaccine in all persons ages ≥18 years, while still acknowledging the increased risk for TTS in women aged <50 years. These women should be aware of the increased risk for TTS and the availability of other FDA-authorized COVID-19 vaccines (i.e., mRNA vaccines).

Although the etiology of TTS associated with the Johnson & Johnson COVID-19 vaccine is unclear, it appears to be similar to another rare immune-mediated syndrome, heparin-induced thrombocytopenia (HIT). Until more information becomes available, experts advise that persons with a history of an episode of an immune-mediated syndrome characterized by thrombosis and thrombocytopenia, such as HIT, should be offered another FDA-authorized COVID-19 vaccine (i.e., mRNA vaccine) if it has been ≤90 days since their illness resolved. After 90 days, patients may be vaccinated with any FDA-authorized COVID-19 vaccine.

Based on current knowledge, experts believe that people with risk factors for VTE (e.g., inherited or acquired thrombophilia including Factor V Leiden; prothrombin gene 20210A mutation; antiphospholipid syndrome; protein C, protein S or antithrombin deficiency), or a prior history of other types of thromboses (including cerebral venous sinus thrombosis [CVST]) not associated with thrombocytopenia are unlikely to be at increased risk for TTS. Likewise, although the risk of thrombosis is increased during pregnancy and the postpartum period, and with certain hormonal contraceptives (e.g., combined oral contraceptives, patch, and ring), experts believe that these factors do not make people more susceptible to TTS after receipt of the Janssen COVID-19 vaccine. These people can receive any FDA-authorized vaccine, including the Janssen COVID-19 vaccine.


Updated: July 13, 2021