Leading COVID-19 Vaccines
The type of vaccines making headlines these past few weeks are mRNA-based COVID-19 vaccine candidates. These vaccines use mRNA, which is genetic material that carries genetic code from a cell’s nucleus to the ribosomes and provides instructions on which proteins to build. In the case of the mRNA vaccines, the ribosomes start making spike proteins based on the viral mRNA in the vaccine. The body perceives these spike proteins as if the body has been infected and starts the process of creating antibodies and other defenses. [4]
“The development of vaccines to combat COVID-19 is critical for our psoriasis patients,” said Dr. April Armstrong, M.D., Professor of Dermatology at the University of Southern California and Chair of the Medical Board of the National Psoriasis Foundation (NPF). “We need to critically evaluate scientific data for these emerging vaccines and interpret these data with special consideration for our patients with psoriasis and psoriatic arthritis. Once available to our patients, we need to carefully monitor their effects in the real world.”
Both Pfizer, in partnership with BioNTech, and Moderna have announced efficacy data for their mRNA vaccine candidates and have filed for U.S. Emergency Use Authorizations. As of December 11, 2020, the U.S. Food and Drug Administration (FDA) issued an emergency use authorization (EUA) for the Pfizer/BioNTech COVID-19 vaccine to be distributed in the U.S. [5] Distribution of the vaccine will be prioritized according to the populations identified by the CDC ACIP guidelines, with health care personnel and residents of long-term care facilities being offered the vaccine first. [6] Pfizer and BioNTech, in collaboration with other vaccine companies, are expected to supply hundreds of millions of vaccine doses to American citizens by the end of 2021. [7]
Following recommendations from the FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC), the FDA has issued an EUA for the mRNA vaccine candidate from Pfizer and BioNTech SE, BNT162b2. [5][8][9] The New England Journal of Medicine published an article on the safety and efficacy of this vaccine, noting that a two-dose regimen of this vaccine was found to be safe and 95 percent effective against COVID-19, according to Phase 3 study data. Data from the study showed that the observed vaccine efficacy against COVID-19 reached full efficacy against the disease at least 7 days after the second dose. [10] Over 43,000 participants were involved in this Phase 3 study, with half receiving the vaccine and the other half receiving a placebo. There were 10 cases of COVID-19, however, 9 cases occurred in the placebo group and 1 in the vaccine group. The incidence of serious adverse events was low, with 4 related serious adverse events reported among vaccine recipients. These adverse effects include shoulder injury related to vaccination, right axillary lymphadenopathy, paroxysmal ventricular arrhythmia, and right leg paresthesia. Overall, the safety profile for BNT162b2 was favorable, with reactogenicity being generally mild or moderate, and reactions less common and milder in older adults compared to younger adults. Systemic reactogenicity was more common and severe after the first dose, but local reactogenicity was found to be similar after both doses. Generally, reactogenicity events were short-lasting. [10]
Moderna’s mRNA-1273 vaccine candidate uses mRNA to encode for a prefusion stabilized form of the surface spike protein [11] Analysis of data from the Phase 3 clinical trial demonstrated a vaccine efficacy of 94.1 percent. While data from the Phase 3 study have not been published in a peer-reviewed publication yet, the company announced 30 severe cases of COVID-19 occurred during the Phase 3 trial, and all 30 cases occurred in the placebo group.11 The company also reported that the majority of adverse events were mild or moderate in severity and included: injection site redness/pain, fatigue, myalgia, arthralgia, headache, and pain. [12]
On December 17, the Center for Biologics Evaluation and Research’s (CBER) and VRBPAC will meet to discuss an EUA approval of the Moderna COVID-19 vaccine for the prevention of COVID-19.
“The first vaccines to be approved for COVID-19 will be mRNA-based. They make the body’s own cells produce pieces of the virus for a certain period of time so that the immune system can be ‘trained’ to see the virus without an actual infection. In this way, the immune system becomes better at clearing the virus when an exposure happens. mRNA vaccines are a new class; we do not know if they change the course of psoriatic disease. The AZD1222 vaccine uses a common cold virus that was modified to look more like the COVID-19 virus to train the immune system,” says Dr. Christoph Ellebrecht, M.D., department of dermatology at the University of Pennsylvania.
Another COVID-19 vaccine candidate is the AstraZeneca/Oxford vaccine (AZD1222), which uses a replication-deficient viral vector that is based on a weakened version of the adenovirus and contains the genetic material of SARS-CoV-2 spike protein. Once vaccinated, the surface spike protein is produced by the body, which primes the immune system to attack the SARs-CoV-2 virus if the person becomes infected later on. [13] Recent clinical trial data are demonstrated the vaccine meeting the primary endpoint of showing protection from COVID-19 occurring 14 days or more after patients received two doses of the vaccine. [13]
The Lancet has also published a peer-reviewed analysis of 4 clinical trials of AZD1222, evaluating its safety and efficacy. The analysis showed that the patients who received two standard doses experienced a vaccine efficacy of 62.1 percent and patients who received a low dose followed by the standard dose experienced an increased efficacy of 90 percent. Overall, efficacy across both groups was 70.4 percent. The vaccine also demonstrated an acceptable safety profile. Of the 11,636 clinical trial participants, 175 severe adverse events occurred in 168 participants: 84 events in the vaccine group and 91 in the control group. Of those events, only 3 were classified as possibly related to a vaccine. [14]
AstraZeneca is preparing to submit the data to regulatory authorities worldwide, seeking conditional or early approval. They are also seeking an Emergency Use Listing from the WHO. [13]
“While these clinical trial data are highly informative, it is equally important to evaluate their effectiveness and safety profile in the real world once they become available to most of our psoriasis community,” said Dr. Armstrong. “We need to exercise extreme caution when deciding whether to attribute an adverse event to the vaccine. Because untoward events can happen regardless of vaccination, we need to examine each case of adverse event following vaccination carefully, paying full attention to the ‘base rate’ of that event in the population before vaccination.”