COMIRNATY

Comirnaty, also known as BNT162b2, is an mRNA-based vaccine developed by Pfizer and BioNTech for the prevention of COVID-19 caused by SARS-CoV-2. It was among the first vaccines to be authorized for use in many countries and has been deployed in global vaccination programs.

The vaccine uses lipid nanoparticles to deliver messenger RNA encoding the SARS-CoV-2 spike protein. Once inside cells, the mRNA is translated into the spike protein fragment, which triggers an immune response, including neutralizing antibodies and T cells that recognize the virus.

A two-dose primary series is administered, with doses typically given several weeks apart (commonly 21 days). It is approved for multiple age groups, with formulations and dosing tailored to different populations. In many regions, booster doses and updated formulations have been authorized to bolster protection against waning immunity and circulating variants.

Storage and handling vary by formulation, but early versions required ultra-cold storage; newer lots have been designed for standard refrigeration for defined periods, facilitating distribution.

Clinical trials and real-world data have shown high efficacy in preventing symptomatic COVID-19 after the primary series, though effectiveness can vary with circulating variants and time since vaccination. Common side effects include injection-site pain, fatigue, headache, and fever. Rare adverse events such as myocarditis and pericarditis have been reported, particularly in younger people after the second dose. Comirnaty has received regulatory approvals or authorizations from major health authorities and is listed for use by the World Health Organization, with ongoing updates as new data emerge.