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Pfizer-BioNTech Comirnaty

Comirnaty’s vaccine is a collaboration of Pfizeri and BioNTech. The European Commission authorized using the vaccine with the conditions on the 21st of December 2020. Comirnaty is used to vaccinate against COVID-19 people who are at least 12- years of age.

  • Comirnaty’s vaccine includes a molecule called mRNA, that has instructions to produce virus protein aka antigen against the SARS-CoV-2 virus that causes of the COVID-19 illness. 
  • The recommended interval of two doses of Pfizer/BioNTech vaccine is six weeks, the maximum protection is achieved on the 7th day after the second dose. 
  • By the recommendation of the Estonian immunoprophylaxis committee, Comirnaty vaccine is safe to use in pregnant women (previous consultation with a doctor is needed) 
  • Comirnaty doesn’t have a virus in it, so it’s not capable of generating the COVID-19 disease.

Additional information

  • Full data about Comirnaty on the website of the European Medical Agency
  • Q&A about Comirnaty on a website of the Estonian Medical Agency In Estonian
  • Comirnaty’s vaccine information (SPC) in Estonian can be found here


How it works?

The objective of the Comirnaty vaccine is to prepare an organism to protect itself against the COVID-19. The mRNA molecule in Comirnaty works as an instruction for cells to produce spike protein. Spike protein is a molecule on the surface of the SARS-CoV-2 virus, and it helps the virus enter the human body. After the vaccination, some cells produce spike proteins based on the information produced by mRNA. The human immune system recognizes the produced spike protein as a dangerous stranger, and starts producing antibodies and specific T-cells, and later, if that person contacts the virus, these will destroy it. The mRNA in the vaccine will be decomposed in a short period of time after the vaccination.

Possible side effects

In this study, the most common side effects of Comirnaty were light or mild, and passed within a couple of days after the vaccination. These included the pain and swelling on the injection spot, tiredness, head aches, muscle and joint pain, chills and fever. More than one people out of ten were affected by these. The redness of the spot of the injection, and nausea, affected less than one people out of ten. Itchiness of the injection spot, joint pain, swollen lymph nods, sleeping disorders and feeling sick affected less than one person out of hundred.

There have been allergic reactions with Comirnaty, including rare adverse reactions (anaphylaxis). These happened during the vaccination campaigns. Like all other vaccines, Comirnaty should be used for vaccination under the medical care.

The ingredients of Comirnaty

The main active ingredient of the vaccine is COVID-19 mRNA. After the dilution, the vial has six 0,3 ml doses, in each of them 30 micrograms of mRNA.

Other ingredients are:

((4-hydroxybutyl)azanediyl)bis(hexane6,1-diyl)bis(2-hexyldecanoate) (ALC0315)
• 2-[(polyethylene glycol)-2000]-N,Nditetradecylacetamide (ALC-0159)
• Distearoylphosphatidylcholine (DSPC)
• Cholesterol
• Potassium chloride
• Monobasic potassium phosphate
• Sodium chloride
• Dibasic sodium phosphate dihydrate
• Sucrose
• Water for injections

What's the efficacy?

A very large clinical trial showed that Comirnaty, given as a two-dose regimen, was effective at preventing COVID-19 in people from 12 years of age.

The trial involved around 44,000 people aged 16 and above in total. Half received the vaccine and half were given a dummy injection. People did not know whether they received the vaccine or the dummy injection.

Efficacy in people aged 16 and above was calculated in over 36,000 participants (including people over 75 years of age) who had no sign of previous infection. The study showed a 95% reduction in the number of symptomatic COVID-19 cases in the people who received the vaccine (8 cases out of 18,198 got COVID-19 symptoms) compared with people who received a dummy injection (162 cases out of 18,325 got COVID-19 symptoms). This means that the vaccine demonstrated a 95% efficacy in the trial.

The trial in people aged 16 years and older also showed around 95% efficacy in the participants at risk of severe COVID-19, including those with asthma, chronic lung disease, diabetes, high blood pressure or obesity.

Everything you should know about the COVID-19 vaccination

Vaccination is free of charge for all people living in Estonia, even without the national health insurance.
  • Vaccination is voluntary.
  • Vaccination is open to all people who are at least 5 years old.
  • Compared to COVID-19 illness, vaccination is safe, and generally, the side effects pass quickly.
  • Booster doses are available only for adults, and the time for a booster jab is 2 months after finishing the vaccination course with the Janssen vaccine, and 3 months after finishing the vaccination course with AstraZeneca, Pfizer/BioNTech and Moderna vaccines.
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