The Race to Find a Coronavirus Vaccine
Do you remember the last normal school day? On March 12, right after I finished taking the National Latin Exam, it was first announced that we would not be having school tomorrow. Since then, we’ve been trapped in our homes (or at least behind masks) for what seems like an eternity, yearning for the day that we can go back to normal. Since last fall, Covid-19, an infectious disease caused by a newly discovered virus, SARS-CoV-2, upended our lives. In order for us to return to a somewhat normal life, a substantial number must become infected to establish “herd immunity” or we need to find vaccines. If we choose to go the route of herd immunity, millions of people could die and our healthcare system could be overwhelmed. The better alternative is for individuals to get vaccinated and induce an antibody response.
In order for the Food and Drug Administration (FDA) to approve a vaccine, it must go through three phases of clinical trials. These experimental trials give some people the actual vaccine, while others receive a placebo. Currently no FDA approved vaccines for Covid-19 exist, but several are going through late-stage trials. In China, labs are testing the inactivated virus for use as a vaccine, which is a common approach, while US companies adopted different methods.
Pfizer and Moderna have employed an innovative technique for vaccine creation that involves the use of mRNA to stimulate coronavirus antibodies. Since the companies using this method do not need to make or deactivate a virus, the process has fewer steps, and they are able to move the trials along faster. Both Pfizer and Moderna are already in phase three.
Originally Pfizer had four different vaccines, but when they tested the vaccines on monkeys, they were able to narrow their choices down to two. In phase two of their trials, they thrillingly found that both versions caused volunteers to produce antibodies and T cells that respond to the virus. One version in particular, called NT162b2, produced significantly fewer side effects and it moved into phase three trials. Moderna’s phase three trial, which began on July 27, is enrolling 30,000 healthy people at about 89 sites around the US. Both vaccines seem promising as of now, but in order for them to be approved by the FDA, they need to be at least 75% effective.
AstraZeneca and Johnson & Johnson, two other companies that entered into the race, are using a common cold virus, Adenovirus, to create vaccines. AstraZeneca’s vaccine is based on a chimpanzee adenovirus, ChAdOx1. Their vaccine creates antibodies against the coronavirus and has shown no severe side effects in Phase 1. The vaccine began phase three trials in the United Kingdom and many other countries. Recently, AstraZeneca had to halt global trials to investigate one trial volunteer who developed spinal cord inflamation. A few days later, they resumed the trial only in the UK. Similarly, J&J is developing a Covid-19 vaccine with Adenovirus 26. They have successfully launched and completed phases one and two and plan on having a phase three trial in Latin America. Adenovirus vaccines may provide longer immunity than other approaches.
Novavax, on the other hand, is using a protein-based vaccine to recreate the spiked protein structures of SARS-CoV-2 to stimulate the immune system. Vaccines for shingles and HPV were also made this way. In August, Novavax finished two preliminary studies conducted on monkeys and humans. Then, they launched a phase two trial in South Africa, which is intended to not only measure the safety of the vaccine, but also its effectiveness. Merck is the only company developing a vaccine that employs vesicular stomatitis viruses, the same approach they successfully used to produce the first approved vaccine for Ebola. They are slightly behind some of the other companies, having just moved their vaccine into phase one. An important difference of Merck’s vaccine is that it has the potential of only needing one dose, while all other frontrunners need two shots of the vaccine.
Despite major advances in technology surrounding the development of vaccines, many questions remain unanswered. Do we have to immunize every month, year, or only once? Can the vaccine be taken orally? Is any vaccine stable enough to distribute across the globe? Dr. Anthony Fauci and other leading scientists predict that the vaccines will be approved by the FDA later this year, and possible widespread distribution could occur early next year, by mid-2021. In late 2021, they are hopeful that people internationally may be able to restore their lives to some semblance of normality.