Janssen COVID-19 Vaccine Booster Side Effects

Janssen vaccines are known to have several side effects. These include Thrombocytopenia, Capillary leak syndrome, and Blood clots. In rare cases, the injection can result in severe or even fatal bleeding. The Janssen vaccine is also known to cause cutaneous small vessel vasculitis, a disorder of the blood vessels of the skin. The symptoms may improve with supportive care.

Janssen COVID-19 Vaccine Side Effects


The Janssen COVID-19 Vaccine can cause thrombocytopenia, a potentially life-threatening condition. In severe cases, the condition can involve unusual thrombus locations, including the pulmonary artery or an extremity vein. Symptoms typically develop within one to two weeks after vaccination.

In post-vaccine patients with symptoms of thrombocytopenia, a platelet count and PF4 ELISA are helpful for determining if thrombocytopenia is the primary cause of VTE. In patients with thrombocytopenia, heparin is not recommended.

Capillary Leak Syndrome

Capillary leak syndrome is a rare but serious condition causing leakage of fluid from small blood vessels. If left untreated, it can lead to organ damage and sometimes even death. While the cause of the condition is unknown, the symptoms can include edema of the arms and legs, low blood pressure, and even faintness. If you suspect you may have the condition, seek medical advice immediately.

Capillary leak syndrome can be very painful. The most common symptom is pain at the injection site. The EMA has reviewed case reports of this condition after vaccination with the COVID-19 vaccine booster manufactured by Janssen. The EMA has ordered healthcare professionals to stop giving the vaccine to individuals with a history of this condition.

Blood Clots

Blood clots are a common side effect of the Janssen covid-19 vaccine booster. The cause is unknown, but increased inflammation in the body appears to be a contributing factor. These blood clots increase the risk of heart attacks and strokes and can damage organs. These side effects can be lifelong and require ongoing monitoring.

The vaccine contains antibodies that activate platelets. When platelets are low, blood clots can form in arteries and veins throughout the body. In rare cases, these blood clots can lead to thrombosis or thrombocytopenia. The symptoms typically appear one to two weeks after the vaccine.


A randomized, placebo-controlled, multinational Phase 3 trial of the COVID-19 vaccine booster (NVX) is underway. The trial is assessing the safety and immunogenicity of NVX-CoV2373 in healthy adults aged 18 to 55 years and elderly individuals aged 65 years and older. The vaccine is an adjuvanted, recombinant spike protein vaccine.

The study identified several adverse events associated with NVX-CoV2373, including rash, myalgia, headache, fatigue, and pain around the injection site. The adverse events were significantly more frequent after the second immunization than in the placebo arm. These side effects were more common in participants aged 18 to 64 years than in older patients.


The efficacy of Janssen’s ChAdOx1 vaccine has been tested in four randomized controlled trials in the U.K., Brazil, and South Africa. In a recent study, the vaccine was effective against both SARS-CoV-2 and symptomatic infections. However, efficacy remained low after a single dose. In an interim efficacy analysis, the vaccine showed an overall efficacy of 70.4%, but only if given in a single dose.

The results of the trial have not yet been published. The trial was single-blinded and randomized. The results are expected by December 2020. The results of the trial will be able to give a clearer idea of the vaccine’s efficacy.

Contraindications to Receiving COVID-19 Vaccine

Contraindications to receiving a COVID-19 vaccine booster are not common, but some should be considered. A person should consult a health care provider prior to getting vaccinated if they have a history of allergic reactions to other vaccines. In addition, a person should not receive this vaccine if they have a history of anaphylaxis.

Those with immediate or severe allergic reactions to some components of the COVID-19 vaccine should seek medical advice before receiving it. This reaction does not need to be life-threatening. People who have an immediate or prolonged allergic reaction to the vaccine’s component polysorbate should not receive the vaccine.