What's TTS Syndrome and Danger Signs you Shouldn't Ignore

What's TTS Syndrome and Danger Signs you Shouldn't Ignore


British pharmaceutical giant AstraZeneca has admitted that its COVID-19 vaccine may result in a rare side effect called thrombosis with thrombocytopenia syndrome (TTS).

  1. The vaccine, which was utilized in India under the name Covishield, was developed by AstraZeneca in collaboration with Oxford University during the pandemic and was manufactured by the Serum Institute of India.

What is Thrombosis with Thrombocytopenia Syndrome (TTS)?

  1. Thrombosis with Thrombocytopenia Syndrome (TTS) is a rare condition in which blood clots form in unusual places in the body such as in the brain (cerebral venous sinus thrombosis) or abdomen.
  2. The condition was observed in people who received adenoviral vector COVID-19 vaccines, such as Vaxzevria, Covishield (AstraZeneca) and the Johnson & Johnson/Janssen COVID-19 vaccine.
  3. TTS seems to occur because the body's immune system reacts to the vaccine by making antibodies that attack a protein involved in blood clotting.

TTS is classified into 2 tiers by the (Center for Diseases Control) CDC:

Tier 1:

  1. Rare blood clots, like in the brain or gut, sometimes alongside more typical ones in the legs or lungs.
  2. Low platelet count (below 150,000 per microliter).
  3. Positive anti-PF4 ELISA tests can help confirm diagnosis but aren't always needed.
  4. Tier 1 cases are usually more severe and riskier.
  5. This is more common in younger people.

Tier 2:

  1. Common blood clots, like in the legs or lungs.
  2. Low platelet count (below 150,000 per microliter).
  3. A positive anti-PF4 ELISA test is necessary for diagnosis.

TTS Symptoms may include:

  1. severe or persistent headaches
  2. vision
  3. shortness of breath
  4. chest pain
  5. leg swelling
  6. persistent abdominal pain
  7. easy bruising
  8. tiny blood spots under the skin beyond the injection site

TTS Danger signs you should not ignore:

  1. While TTS is rare, individuals who have received vaccines associated with TTS should be alert for symptoms and seek medical attention immediately if they experience any within a few weeks of vaccination. Early identification and treatment is essential to effectively manage TTS.

AstraZeneca's vaccine:

  1. The vaccine, marketed worldwide under various names including Covishield and Vaxzevria, was produced by the Serum Institute of India.
  2. Unlike mRNA vaccines, Covishield is based on the viral vector platform, utilizing a modified chimpanzee adenovirus to deliver the COVID-19 spike protein into human cells.

Covishield and Covaxin are two primary COVID-19 vaccines that were used extensively in India. Here's the key differences:




  1. Technology


  • Viral vector vaccine. It uses a weakened version of a chimpanzee adenovirus modified to contain genetic material from the SARS-CoV-2 spike protein.
  • Inactivated virus vaccine. It uses a whole, inactivated (killed) SARS-CoV-2 virus to trigger an immune response.
  1. Manufacturer


  • Developed by Oxford University and AstraZeneca. Manufactured in India by the Serum Institute of India (SII).
  • Developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR).
  1. Storage
  • Can be stored at standard refrigerator temperatures (2-8 degrees Celsius), making transportation and distribution easier.
  • Also stored at standard refrigerator temperatures (2-8 degrees Celsius).


Here's a list of some COVID-19 vaccines and their countries of origin:

COVID-19 vaccine

Countries of origin

  1. Ad26.COV2.S (Johnson & Johnson/Janssen): Viral Vector Vaccine (Adenovirus-based)
  • The Janssen COVID19 vaccine, sold under the brand name Jcovden, is a COVID19 vaccine that was developed by Janssen Vaccines in Leiden, Netherlands, and its Belgian parent company Janssen Pharmaceuticals, a subsidiary of American company Johnson & Johnson.
  1. Pfizer-BioNTech: mRNA Vaccine
  • Pfizer and BioNTech are manufacturing the vaccine in their own facilities in the United States and in Europe.
  1. Spikevax (Moderna): mRNA Vaccine
  • The Moderna COVID19 vaccine, sold under the brand name Spikevax, is a COVID-19 vaccine developed by the American company Moderna, the United States National Institute of Allergy and Infectious Diseases (NIAID), and the Biomedical Advanced Research and Development Authority (BARDA).
  1. Oxford–AstraZeneca vaccine: Viral Vector Vaccine (Adenovirus-based)
  • Oxford–AstraZeneca COVID-19 vaccine, also known as Vaxzevria, was developed in the United Kingdom by Oxford University and AstraZeneca, a British-Swedish company. The vaccine is a viral vector vaccine that uses the modified chimpanzee adenovirus ChAdOx1 as a vector.
  1. Covishield: Viral Vector Vaccine (Adenovirus-based)
  • India (manufactured by Serum Institute of India under license from AstraZeneca) - Same vaccine as Vaxzevria, different brand name
  1. CoronaVac (Sinovac Biotech): Inactivated Virus Vaccine
  • Chinese biopharmaceutical company based in Haidian District, Beijing that focuses on the research, development, manufacture, and commercialization of vaccines that protect against human infectious diseases.
  1. Sinopharm COVID-19 Vaccine: Inactivated Virus Vaccine
  • In April 2020, China approved clinical trials for a candidate COVID-19 vaccine developed by Sinopharm's Beijing Institute of Biological Products (BIBP) and the Wuhan Institute of Biological Products (WIBP).
  1. Sputnik V (Gamaleya Research Institute): Viral Vector Vaccine (Adenovirus-based)
  • Sputnik V, also known as Gam-COVID-Vac, is a COVID-19 vaccine developed by Russia's Gamaleya Research Institute of Epidemiology and Microbiology. It is an adenovirus viral vector vaccine.

Explanation of vaccine Types:

  1. Viral Vector Vaccines: Use a modified, harmless virus (like an adenovirus) as a carrier to deliver genetic instructions for making the SARS-CoV-2 spike protein, triggering an immune response.
  2. mRNA Vaccines: Contain messenger RNA (mRNA), a genetic blueprint that teaches cells to make the SARS-CoV-2 spike protein, triggering an immune response.
  3. Inactivated Virus Vaccines: Use a whole SARS-CoV-2 virus that has been killed or inactivated so it cannot cause infection, but still stimulates an immune response.

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