Table I.

Review of COVID-19 vaccines in development

Type of vaccine (approved examples)	Description	Example companies and phase of development	Anticipated risk to patients on immunotherapeutics
Inactivated virus	SARS-CoV-2 is allowed to replicate in cells and then killed by using chemicals, heat, or radiation	•Sinovac: approved (not in United States) •Sinopharm: approved (not in United States)	None
Live, attenuated virus	SARS-CoV-2 is genetically engineered to limit infection and reproduction	•Serum Institute and Codagenix: phase 1	Low
Protein subunit	SARS-CoV-2 protein is engineered and produced to stimulate antiviral antibodies	•Novavax (NVX-CoV2373): phase 3	None
Virus-like particles	Virus-like structures enter cells like virus to deliver SARS-CoV-2 protein subunit to stimulate immune response	•Medicago/GlaxoSmithKline: phase 3	None
Nonreplicating viral vectors	Nonreplicating engineered viruses, such as adenovirus or vaccinia, that carry genetic code for proteins of the SARS-CoV-2 virus to stimulate an immune response	•University of Oxford/AstraZeneca (ChAdOx1/AZD1222): approved (expected in United States) •Johnson & Johnson (JNJ-78436735): approved in United States	None to minimal
Replicating viral vectors	Weakened versions of carrier viruses, like influenza or measles, that can replicate in the body and carry genetic code for a protein of SARS-CoV-2. Do not usually cause symptoms.	•University of Pittsburgh/Themis Biosciences/Institut Pasteur/Merck: phase 2	Minimal
RNA	RNA is injected into the body that codes for a SARS-CoV-2 protein that is then produced and leads to antibody development.	•Moderna/National Institute of Allergy and Infectious Diseases (mRNA-1273): approved in United States •BioNTech/Fosun Pharma/Pfizer (BNT162): approved in United States	None
DNA	DNA is injected into the body, often in the form of a plasmid, that codes for a SARS-CoV-2 protein that is then produced and leads to antibody development.	•Inovio/International Vaccine Institute: phase 3 •Cadila Healthcare: phase 2 •Osaka University/AnGes/Takara Bio: phase 2	None

SARS-CoV-2, Severe acute respiratory syndrome coronavirus 2.