The Center for Immunization Research at the Johns Hopkins Bloomberg School of Public Health reconfigured both of its adult vaccine study teams to focus on Phase 3 clinical research for COVID-19 vaccine candidates developed by Pfizer/BioNTech and AstraZeneca. Brittany Feijoo answers common questions about the vaccine trials underway at the center.
I am directly involved with the clinical trials for the Pfizer/BioNTech and AstraZeneca vaccines. My role as a Sub-Investigator is to evaluate volunteers during the trials.
Vaccines are first tested in a small number of healthy volunteers in Phase 1 and Phase 2 studies to determine safety and immune response. Phase 3 trials involve thousands of volunteers to test for safety and efficacy. In the COVID-19 Phase 3 vaccine trials, individuals with well controlled underlying medical conditions were also included. The purpose was to determine the effects of the vaccine in people representative of the general population. Some of the underlying medical conditions of participants included heart disease, obesity, diabetes, liver disease, and HIV. The trials enrolled an incredibly diverse pool of volunteers – in gender, age, underlying medical conditions, and demographics.
Generally speaking, most vaccine trials are made up of individuals of Caucasian background. We normally do not have a good representation of African Americans and Hispanics. This is largely due to the mistrust and distrust in research trials as a result of past occurrences such as The Tuskegee Syphilis Study. However, for the COVID-19 vaccine trials, there was a concentrated push and a goal of the federal government’s Operation Warp Speed and the affiliated Coronavirus Prevention Network to represent the general population. Vaccine research centers were able to recruit and enroll minority populations through national and local advertising as well as community engagement efforts. Pfizer/BioNTech and Moderna enrolled approximately 10% African American volunteers and approximately 20% Hispanic/Latinx volunteers.
There are numerous types or platforms of COVID-19 vaccines. The two leading platforms in the United States are the messenger RNA, or mRNA, and the viral vector vaccine.
The mRNA vaccine, which includes the Pfizer/BioNTech and Moderna vaccines, takes the RNA genetic material from the spike protein in the SARS-CoV-2 virus – which causes COVID-19 –and encases it in a lipid nanoparticle. It needs to be encased because RNA is highly unstable and can degrade easily. This material is then inserted into the cytoplasm of a cell, not the nucleus. The nucleus is where DNA is made and people worry that an mRNA vaccine is going to change your DNA. It does not change your DNA. Once it’s in your cytoplasm, your body starts to replicate the proteins. They then travel to your lymphatic system where your body recognizes it as a foreign invader and starts to generate antibodies. Your body will then have an understanding of what the antigen is, so if you get infected with the SARS-CoV-2 virus you have the antibodies in reserve to fight it. The memory is there.
The viral vector vaccine from AstraZeneca and Johnson & Johnson utilizes a method that has been used in previously licensed vaccines. It takes a part of the spike protein from the SARS-CoV-2 virus that causes COVID-19 and inserts it into a common cold virus. It is then inserted into your cells, which causes your body to produce antibodies against COVID-19. Oftentimes, people think it’s more ‘natural’ because it contains actual viral protein and not genetic material like with the mRNA vaccine. However, both vaccine platforms are safe and do not change or alter your DNA.
We do not know how long the vaccines will provide protection against COVID-19. We do know that the coronavirus does not mutate as quickly as the flu. As of now, we do not think this will be a yearly vaccine, but we may need boosters from time to time. As a result, several of the vaccine sponsors are developing potential booster doses.
Although the percentages in efficacy may vary by vaccine, we are confident that all of the vaccines are effective against severe disease, hospitalization, and death. And from a public health standpoint that is crucial.
Is it possible to still get COVID-19 after vaccination? Yes, but most likely with mild symptoms or asymptomatic infection. This is why masking and physical distancing are still very important.
The common concern is that the COVID-19 vaccines were developed too fast and that they do not have full approval. It is important to know that Emergency Use Authorization from the Food and Drug Administration does not mean safety was compromised. All of the same safety protocolswere followed as with other vaccine trials. It has been authorized for use because interim data analysis indicated that these vaccines were both safe and very efficacious. They each have been evaluated in over 30,000 participants. Pfizer had over 43,000 participants. And safety evaluations are still ongoing. Everyone in the trials is being followed for two years. When you get your vaccine you have the option of signing up for V-safe, which is a way that the Centers for Disease Control and Prevention is tracking adverse events. You can download an app on your phone and report any symptoms. There is also the FDA’s Vaccine Adverse Event Reporting System.
It is remarkable how quickly the vaccines have been developed, but this occurred for several reasons. First, a large majority of the vaccine scientific community has been working on COVID-19 since the start of the pandemic. At our Center, we typically conduct Dengue, ETEC, RSV, Influenza, Ebola and Shigella vaccine trials but we all shifted focus to COVID-19. Second, scientists have been studying coronaviruses for a long time, including SARS-CoV-1 (Severe Acute Respiratory Syndrome Coronavirus) in 2003 and MERS (Middle Eastern Respiratory Syndrome) in 2012. Third, we had a large number of people willing to participate in these vaccine trials.
It’s been shocking to all of us in vaccine research that we were able to recruit so many thousands of volunteers. I often ask them why they participated and they say they ‘had to do something’ to help resolve the pandemic. Or they know someone who died or suffered from COVID-19 or they work in medicine or science and they understand the value of trials.
Lastly, trials are very expensive. But the federal government’s support has alleviated the delays associated with lack of funding.
Current safety reports have shown that some people who have had severe allergic reactions to polyethylene glycol, or PEG, could have an allergic reaction to the mRNA vaccine. Scientists believe the coating that encases the spike protein in the mRNA vaccine may be similar to PEG. The CDC recommends that these individuals not get one of the mRNA vaccines at this time. They recommend these individuals consult with an allergist-immunologist to determine if they can safely receive the vaccine.
This also applies to individuals with allergic reactions to polysorbate, a similar substance to PEG. Any person who has had a severe or immediate allergic reaction after the first dose of an mRNA vaccine should not receive another dose. Individuals with severe allergic reactions to other vaccines or components can still get the mRNA vaccine but will be monitored for 30 minutes after vaccination.
Currently, only the Pfizer vaccine is authorized for children, and it’s only for ages 16 and older. The data have shown that children do not get as severely ill as adults do from COVID-19. But there is a concern for a condition called Multisystem Inflammatory Syndrome in Children (MIS-C). Although it is rare, some children who have had COVID-19 develop inflammatory responses that affect different organs and tissues in their bodies, which can make them seriously ill. And this has been seen even in children who had COVID-19 but were asymptomatic.
Once a safe and effective vaccine becomes available for children under the age of 16, vaccinating this population is important. Especially to prevent MIS-C, which in the United States has been diagnosed more often in African American and Hispanic children. So far, Pfizer has evaluated the vaccine down to the age of 12 and plans to begin Phase 1 trials for children between the ages of 5 and 11 in the next few months.