The first clinical trial of a vaccine targeting coronavirus disease 2019 (COVID-19) has begun at Kaiser Permanente Washington Health Research Institute in Seattle, USA. If successful, the vaccine will prevent infection with the SARS-CoV-2 virus that causes COVID-19 in patients who have not previously been exposed.
Developed by researchers at Moderna Inc, a biotechnology firm in Cambridge, Massachusetts, USA, with financial and technical support from the USA National Institute of Allergy and Immunology (NIAID) Vaccine Research Center, the mRNA-1273 vaccine targets the spikes on the coronavirus surface that attach to and allow it to enter human cells. Rather than using neutralised virus to develop the vaccine from scratch, the mRNA-1273vaccine was based on an existing vaccine platform developed for related corona viruses causing severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).
Once the genetic sequence for the SARS-CoV-2 spike was available, scientists were able to quickly develop a gene sequence to express the stabilised spike protein. Injecting this messenger RNA sequence causes the body to generate proteins that should provoke the host immune system to develop antibodies targeting the SARS-CoV-2 virus. Building on this earlier coronavirus research allowed the vaccine to reach clinic trials in record time, according to a statement by NIAID Director Anthony S. Fauci MD.
The current study is testing three dose levels of mRNA-1273 in a Phase 1 ascending dose study in 45 healthy patients. Fifteen patients each will receive two doses of 25 micrograms, 100 mcg or 250 mcg about 28 days apart. The first four participants have received the 25 mcg dose. Their progress will be reviewed for safety before the remaining 25 mcg and the 100 mcg group are injected. A second safety review will be conducted before injecting the 250 mcg group. Patients will be followed for one year after the second shot. If this study is successful, Phase 2 and 3 studies would also need to be conducted, possibly making the vaccine clinically available in about 18 months.
“Finding a safe and effective vaccine to prevent infection with SARS-CoV-2 is an urgent public health priority,” Dr Fauci said. “This Phase 1 study, launched in record speed, is an important first step toward achieving that goal.”