COVID-19 Vaccine Trials Speed Up

June 26, 2020

Vaccine candidates for COVID-19 are going through clinical trials at a faster rate than for any other disease.

Vaccine candidates for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the United States, the United Kingdom, and other countries are going through clinical trials at a faster rate than for any other disease in history. Some experts say a vaccine will be ready by the end of this year.

Moderna, for example, is in late-stage development of mRNA-1273, its vaccine candidate against coronavirus disease 2019 (COVID-19). Moderna finalized the phase 3 study protocol based on feedback from FDA, it said in a press release.1

The randomized, 1:1 placebo-controlled trial is expected to start in July, and will include around 30,000 participants, Moderna said. Moderna remains on track to be able to deliver approximately 500 million doses— and possibly up to 1 billion doses—per year, starting in 2021. Moderna expects to begin the phase 3 study in July, according to the release.1

Another promising vaccine candidate, ChAdOx1 nCoV-19, from the University of Oxford in the United Kingdom recently entered phase 2/3 trials.

"The clinical studies are progressing very well and we are now initiating studies to evaluate how well the vaccine induces immune responses in older adults, and to test whether it can provide protection in the wider population,” said Professor Andrew Pollard, head of the Oxford Vaccine Group, in a press release.2

The phase 2 part of the study involves expanding the age range of individuals the vaccine is assessed in, to include a small number of older adults aged 56 to 69 years and aged over 70 and children aged between 5 to 12 years. In the phase 3 part of the study, investigators will assess how the vaccine works in a large number of individuals over the age of 18. Adult participants in both phase 2 and phase 3 groups will be randomized to receive 1 or 2 doses of either the ChAdOx1 nCoV-19 vaccine or a licensed vaccine (MenACWY) that will be used as a control.2

AstraZeneca, which will develop, manufacture, and distribute3 the Oxford vaccine when it is ready, said it reached an agreement with the Inclusive Vaccines Alliance of Europe to supply as many as 400 million doses of the vaccine, starting by the end of the year.4

Estimates for the availability of a COVID-19 vaccine in the United States keep changing, ranging from later this year to early next year.

Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Disease, said that, if everything goes right, a vaccine could be available in November or December.5

Similarly, National Institutes of Health Director Francis S. Collins, MD, PhD, said that 4 or 5 vaccine candidates show promise of being ready for production quickly—possibly as early as this fall—during a live JAMA Network YouTube event on May 19.6


1. Moderna advances late-stage development of its vaccine (mRNA-1273) against COVID-19. Press release. Moderna; June 11, 2020. Accessed June 25, 2020.

2. Oxford COVID-19 vaccine to begin phase II/III human trials. Press release. Oxford University; May 22, 2020. Accessed June 25, 2020.

3. AstraZeneca and Oxford University announce landmark agreement for COVID-19 vaccine. Press release. AstraZeneca; April 30, 2020. Accessed June 25, 2020.

4. McCurdy, Christen. AstraZeneca to deliver 400M vaccine doses to Europe once approved. UPI. June 13, 2020. Accessed June 25, 2020.

5. Vogt, Adrienne. Fauci says he thinks a coronavirus vaccine is still on track for the end of 2020. CNN. May 27, 2020.

6. Coronavirus Q&A: Accelerating Therapies and Vaccines. JAMA Network YouTube event. May 19, 2020.