With thousands of articles published weekly on COVID-19, navigating the literature on this emerging infectious disease can be daunting. To help health care professionals and the general public keep up and to fight medical misinformation, a group of emergency physicians started the website Brief19.com, which publishes analysis of COVID-19 research and policy five days a week, all for free. Here are highlights from recent Briefs. (Note: ACEP Now’s medical Editor in Chief, Jeremy Samuel Faust, MD, MS, MA, FACEP, is also Editor in Chief of Brief19.)

Face masks, face shields, and social distancing are likely our new normal for the foreseeable future. The prospects of achieving herd immunity in the United States without a vaccine appears grim.¹ The literature on SARS-CoV-2 vaccine development is growing, with approximately 248 candidate vaccines at the time of this writing.² Nevertheless, there are several fundamental concepts regarding vaccine development for SARS-CoV-2 that are broadly applicable and important to understand.

The Ideal Vaccine

An ideal vaccine should be effective in preventing symptomatic disease (eg, measles, mumps, and rubella vaccine), significantly reducing illness severity (eg, seasonal influenza vaccine), or preventing seroconversion to prevent infection altogether.^3,4 The ideal vaccine is multivalent and provides long-lasting immunity. The World Health Organization (WHO) recommends that effective vaccines should show a risk reduction of at least 30 percent.⁵

The ideal vaccine should be safe, ranging from no side effects to relatively minor side effects, such as headache, low-grade fever, injection site reaction, and myalgias.

Finally, the ideal vaccine should be cost-effective, be easy to administer, require a minimum number of administrations, and not require special storage conditions.^4,6

Vaccine Development

The development of safe and effective pharmaceuticals takes, on average, 13 years from the time of discovery to Food and Drug Administration (FDA) approval.⁷ The overall failure rate of pharmaceuticals to make it through this entire process exceeds 95 percent. In the late spring, it was estimated that a SARS-CoV-2 vaccine would be available within 12 to 18 months.⁸ While such estimates were seen by many as naive idealism, there are a few reasons such a timeline now looks more likely. Let’s dive in.

To begin, let’s identify important questions in the vaccine life cycle, which include:⁹

1. Which antigens produce an immune response? (preclinical studies)
2. How safe is the vaccine? (Phase I clinical trials)
3. What dose is required for immunity? (Phase II clinical trials)
4. How effective is the vaccine? (Phase II and III clinical trials)
5. What is the long-term safety and efficacy in the general (heterogenous) population? (Phase IV clinical trials)

Thankfully, SARS-CoV-2 vaccine development is not starting from scratch. Attempts to develop a vaccine for coronavirus have been ongoing for years. Numerous groups have worked on a vaccine since the MERS-CoV and SARS-CoV epidemics.¹⁰