ALC-0159

ALC-0159

ALC-0159 is a lipid nanoparticle used in the formulation of the Pfizer–BioNTech COVID-19 vaccine, also known as BNT162b2. It is one of the four lipids in the vaccine that encapsulate the mRNA (messenger RNA) to protect it from degradation and help it enter cells.

Composition

ALC-0159 is a polyethylene glycol (PEG)-lipid conjugate. The PEG-lipid conjugate is used to increase the stability of the lipid nanoparticle and prolong the circulation time of the mRNA in the body. The PEG-lipid conjugate consists of two parts: a lipid anchor and a PEG chain. The lipid anchor is a phospholipid that can insert into the lipid nanoparticle, while the PEG chain extends out from the surface of the nanoparticle.

Role in Pfizer–BioNTech COVID-19 Vaccine

In the Pfizer–BioNTech COVID-19 vaccine, ALC-0159 forms part of the lipid nanoparticle that encapsulates the mRNA encoding the SARS-CoV-2 spike protein. The lipid nanoparticle protects the mRNA from degradation in the body and helps it enter cells. Once inside a cell, the mRNA is released and used as a template to produce the spike protein, which triggers an immune response.

Safety

The safety of ALC-0159 is supported by data from preclinical and clinical studies of the Pfizer–BioNTech COVID-19 vaccine. However, there have been reports of allergic reactions to the vaccine, which may be due to the PEG component of ALC-0159. These reactions are rare and are usually mild to moderate in severity.

See also

• Pfizer–BioNTech COVID-19 vaccine
• Lipid nanoparticle
• mRNA
• SARS-CoV-2