COVID-19 Vaccines: Progress, Promise, and Place in the Pandemic

The year 2020 is mercifully drawing to a close. It is a year that most will wish farewell to and look to a better year and years to come. Most notable in 2020 was the emergence of the COVID-19 pandemic that actually began in December of 2019 in China, and at the time of this writing is still ravaging the world’s population including the U.S. But in this year there has been truly remarkable progress in creating a weapon against the virus – a new vaccine to combat it.

A Little Background

The reason the pandemic is so ferocious and widespread is that it is a novel coronavirus. Its name now is officially the SARS-CoV-2 or Severe Acute Respiratory Syndrome Coronavirus 2. Because it is “novel” or new it means that humans have no natural immunity to it so many exposed to it can get infected. Thus, one strategy in the larger fight against the pandemic is to make the population immune to the virus by creating a vaccine specifically designed to elicit an immune response. This will combat the virus when we are exposed and keep us healthy.

In essence, scientists around the world are racing to create a vaccine that will trick the body into producing an immune response to the COVID-19 virus without having the actual disease. This is exactly what a vaccine does: it fools our innate complex immune system into producing antibodies and protective white blood cells (T cells) that will destroy the foreign virus when it tries to set up shop within our body.

How a Vaccine Works

The essence of how a vaccine works is illustrated in the figure below. The COVID-19 virus makeup is known. Scientists can manufacture vaccines that combine some of the foreign protein from the virus with other material. The vaccine causes the body’s immune system to recognize that this foreign protein introduced into the body’s cells must be eradicated using the body’s very effective immune response. The immune system enables the body’s white blood cells (as opposed to red blood cells that carry oxygen to the tissues), B-lymphocytes and T-lymphocytes, to produce antibodies and attack cells, respectively. These antibodies and attack cells are designed specifically to destroy the COVID-19 virus. Once the immune response is mounted, which usually takes two vaccinations and at least a month, the immunized person can disable or kill the threatening virus – thus making the person immune to the virus.

There are over 100 candidate virus vaccines in various stages of development including large Phase III trials. The candidate vaccines use a wide variety of strategies to develop the immune response, but all are intended to create the immune response that will be safe and effective in combating the COVID-19 virus. As development continues it is probable that some of the vaccines will be more effective in particular populations giving doctors and public health officials even more precise weapons to use against the virus.

The Vaccine Approval Process

In the U.S. the Food and Drug Administration (FDA) is in charge of determining whether a vaccine is safe and effective and approved for human use. This requires animal testing to prove that the vaccine works in animals exposed to the virus, human safety trials, and then the large Phase III trials to show that vaccinated people are protected against the contracting the disease.  The three phases of vaccine research are: Phase I – safety and immune response; Phase II – dose finding studies and safety; and Phase III with placebo and vaccine-treated groups involving tens of thousands of volunteers to demonstrate effectiveness and safety. The FDA reports they are looking for a vaccine to approve that provides at least 50% protection to those given the vaccine. Once approved based on the efficacy and put into use, those vaccinated will be followed closely for two years to be certain that there are no safety concerns with the widespread use.

Because of the severity of the pandemic now, it is believed that, once the FDA is satisfied based on the scientific review of the clinical trial data, they will allow vaccines to be used for Emergency Use Authorization (EUA). The EUA will allow the administration within a period of days to thousands of targeted high-risk individuals. As the vaccine production increases, and assuming there are no risk/benefit surprises, the drug will then be approved for general use as part of the overall strategy to help get the pandemic under control.

The Pfizer and BioNtech Vaccine

On Monday November 9, 2020 (six days after the U.S. Presidential election), Pfizer and BioNtech reported the results of an interim analysis of their Phase III trial designed to enroll about 44,000 people. Interim analysis is a scientific look at the results of a still-ongoing clinical trial. There were 94 cases of COVID-19 infection in the 40,000 volunteers at the time of the interim analysis. The results revealed that the efficacy rate was 90% in the vaccinated group – meaning that of the 94 confirmed case 90% were in the placebo group. The vaccine thus appears to confer immunity at a high level and with minimal side effects such as injection site soreness, fatigue, headache, chills, muscle pain, and joint pain. Although the final analysis of the still-ongoing trial will continue, the drug manufacturers plan to ask the FDA for EUA release of the drug in the third week in November, and it is likely the FDA will expedite this review. It is entirely possible that this vaccine may receive EUA by the end of 2020! This represents the unprecedented development and approval of a vaccine to a previously unknown virus all within one calendar year. It is a truly remarkable feat of science, private enterprise, and government all working together to accomplish what would have been considered the impossible only a year ago.