Red Blood Cells Play Significant Role in Immune System, Bind Cell-Free DNA
October 26, 2021 01:40pm
By Skylar Kenney, Assistant Editor
Telling personal stories about receiving the vaccine and using a direct, fact-based approach can both answer patient’s questions and demonstrate safety when advising them on COVID-19 vaccines.
With 3 FDA-approved COVID-19 vaccines and other potential candidates in the pipeline, addressing patients’ concerns and questions about the vaccines requires up-to-date information and careful review.
A session at the National Association of Pediatric Nurse Practitioners (NAPNAP) 2021 National Conference on Pediatric Health Care reviewed the latest information on COVID-19 vaccines. Presenter Dana DeShon, CNP, said that although the development process for COVID-19 vaccines has been accelerated, it is important to reassure patients that there were no shortcuts for safety and efficacy.
In addition to the Pfizer and BioNTech, Moderna, and Johnson & Johnson vaccines, which have received FDA approval, DeShon said there were 223 candidate vaccines as of December 2020, including 57 clinical phase vaccines and 166 pre-clinical phase vaccines. She explained that after vaccine candidates receive approval for testing in humans, they go through 4 phases. Phases 1 through 3 are conducted prior to FDA review, with increasing numbers of participants. Phase 4 is conducted after FDA review and involves 1000 or more participants.
Following this general review, DeShon explained the various approaches to vaccine development, such as DNA, non-replicating viral vectors, or purified protein.
The DNA approach to vaccine development involves getting DNA into the nucleus of the cell. A vaccine candidate by Inovio Pharmaceuticals uses this approach, with a phase 1 trial that began in April 2020 and a phase 2/3 trial that launched in November 2020. This vaccine requires 2 doses and is stable at room temperature for more than a year, with a 5-year projected shelf life at normal refrigeration temperatures. When counseling patients on DNA vaccines, DeShon said it is important to note that they enter the cell but do not change the recipient’s own DNA.
The Johnson & Johnson vaccine is an example of a non-replicating vital vector vaccine, which originates from a carrier virus, such as the adenovirus or pox virus. DeShon said a gene is inserted into a vector virus to code it, and it is important to note that the virus vector does not reproduce in the vaccine recipient.
The immune system then creates antibodies against proteins such as the COVID-19 spike protein, and antibodies directed against the spike protein will prevent COVID-19 from binding to the cell and thus prevent infection. In these vaccines, DeShon said the only concern could be if a patient had previous exposure to COVID-19, which could negatively impact the body’s response.
The vaccines from Pfizer/BioNTech and Moderna are both messenger ribonucleic acid (mRNA) vaccines. This approach is composed of a piece of the virus’s genetic code surrounded by lipids. Notably, it does not interact with DNA and patients cannot get COVID-19 from the vaccine.
The Pfizer and BioNTech vaccine demonstrated 95% efficacy against COVID-19 in a clinical trial of 43,448 participants, 21,720 of whom received the vaccine and 21,728 of whom received a placebo. Investigators observed 170 cases of COVID-19 with onset at least 7 days after the second dose, 162 of whom were in patients who received the placebo. They also found a response beginning 12 days after the first dose and 7 days after the second dose.
Notably, the Pfizer and BioNTech vaccine is the only one to be approved for individuals aged 16 years and older, as Moderna and Johnson & Johnson are approved for 18 years of age and older. The FDA approved the Pfizer/BioNTech vaccine in October to begin clinical trials in patients as young as 12 years of age.
Moderna’s vaccine is also an mRNA vaccine. In a clinical trial with 27,817 participants, 11 cases of COVID-19 were reported in the vaccinated group and 185 cases were reported in the placebo group as of November 21, 2020. Notably, there were no severe cases in the vaccinated group. Researchers found 80.2% protection 2 weeks after the first dose and 94.1% protection after the second dose.
DeShon said that safety monitoring for the mRNA vaccines did see some cases of anaphylaxis. Of patients who experienced this, 86% had onset within 30 minutes of vaccination and 81% had a history of allergies or allergic reactions. The most common adverse reactions include injection site pain, fatigue, headache, muscle pain, joint pain, and chills.
For patients who have concerns about vaccine safety and adverse effects, DeShon said clinicians have several options to bolster trust. Telling personal stories about receiving the vaccine and using a direct, fact-based approach can both answer their questions and demonstrate safety.
DeShon, Dana. COVID-19 Vaccine. National Association of Pediatric Nurse Practitioners; March 26, 2021. Virtual; Accessed March 26, 2021.