Dozens of COVID-19 vaccines are currently in development. Which show promise, and which are dead ends? Just as importantly, when will they be ready?
“Vaccine development is usually measured in years and sometimes even decades,” Dr. Amesh Adalja, a senior scholar at the Center for Health Security at Johns Hopkins University, explains. “And there are some infectious diseases for which we have no vaccine after decades and decades of work, like HIV or hepatitis C, for example.”
Yet U.S health officials and pharmaceutical companies expect to have a reliable coronavirus vaccine ready as early as January 2021. At the moment, these contenders show the most promise to become final, approved COVID-19 vaccines.
Moderna Therapeutics: mRNA-1273
In late July, Moderna and the NIH launched America’s first Phase 3 clinical trial of a coronavirus vaccine.
“Results from early-stage clinical testing indicate the investigational mRNA-1273 vaccine is safe and immunogenic, supporting the initiation of a Phase 3 clinical trial,” explained NIAID Director Anthony Fauci. “This scientifically rigorous, randomized, placebo-controlled trial is designed to determine if the vaccine can prevent COVID-19 and for how long such protection may last.”
The ultimate goal of Moderna’s Phase 3 trial is to determine if the vaccine can prevent symptomatic COVID-19 after two doses. Researchers will all study the data to find whether mRNA-1273 can prevent severe COVID-19 or laboratory confirmed SARS-CoV-2 infection with or without disease symptoms.
Results may be available as soon as November, and Moderna aims to deliver at least 500 million doses per year beginning in 2021.
Pfizer: BNT162b2
Pfizer’s vaccine candidate BNT162 contains genetic material called messenger RNA, or mRNA. This genetic code sends cells a message that helps them build an immune response to the COVID-19 virus. BNT162 actually exists in four different forms, each representing different mRNA formats and target antigens.
On July 27, Pfizer and partner BioNTech launched a trial that combines phase two and three by enrolling a diverse population in areas with significant coronavirus infection. A total of 30,000 people will be examined with the goal of seeking regulatory review as early as October 2020. Pfizer hopes to supply 1.3 billion doses by the end of 2021.
University of Oxford: ChAdOx1 nCoV-19
Coronavirus vaccine candidate ChAdOx1 nCoV-19 is made from a genetically engineered virus that causes the common cold in chimpanzees. Though at first glance that might sound unlikely to prevent COVID-19, University of Oxford researchers explain that the virus has been heavily modified to “look” more like coronavirus.
During the development of ChAdOx1 nCoV-19, Oxford scientists transferred the genetic instructions for the coronavirus’s “spike protein” into the vaccine. The spike protein is the essential tool the coronavirus uses to invade human cells. By arming the vaccine with those spike proteins instead, scientists believe that ChAdOx1 nCoV-19 can safely resemble the coronavirus and teach the immune system how to attack it.
Early results from phase one and two of clinical testing revealed the vaccine triggers a strong immune response. Now ChAdOx1 nCoV-19 has entered phase three of its clinical trial and aims to recruit up to 50,000 volunteers in Brazil, the UK, the U.S, and South Africa.
The bottom line? With so many strong contenders, it’s only a matter of time until we have a reliable COVID-19 vaccine. It’s much-needed good news in a period of great uncertainty.
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