Clinical trials for COVID-19 vaccines have been long anticipated since March 2020, but now that they’ve arrived, the news isn’t all positive.
According to reports from clinical trials by Moderna and Pfizer, a small number of patients experienced intense side effects after receiving injections of an experimental coronavirus vaccine.
Exploring and tracking these side effects will be instrumental in determining the safety and efficacy of long-awaited vaccines nearly a year after the pandemic first began.
Pfizer’s BNT162 Vaccine
U.S.-based pharmaceutical giant Pfizer, in partnership with German drugmaker BioNTech, announced at the end of April that the first human participants in the United States have been dosed with a potential vaccine known as BNT162.
Now the experimental vaccine is in late phase testing. This vaccine contains genetic material called messenger RNA, or mRNA. Its genetic code sends cells a message that helps them build an immune response to the COVID-19 virus. BNT162 actually exists in four different forms, each representing different mRNA formats and target antigens.
On September 9, Pfizer released a statement on the results of clinical data to date: “We are encouraged by the data thus far and confident in our progress towards developing a safe and effective vaccine candidate to help address this current pandemic.”
A total of two participants who received Pfizer’s BNT162 experimental vaccine reported intense side effects including high fever, pounding headaches, intense chills, and exhaustion. One of the volunteers also experienced similar side effects to Hutchinson’s disease after being administered his second dose of the two-dose vaccine candidate.
Fortunately, these side effects diminished after one day or less.
Moderna’s investigational vaccine is known as mRNA-1273. According to the NIH, Moderna’s investigational vaccine “directs the body’s cells to express the spike protein to elicit a broad immune response” against COVID-19.
Phase 1 and 2 clinical trials found mRNA-1273 vaccine to be safe and able to induce antibodies with strong virus-neutralizing activity.
Moderna’s Phase 3 clinical trial is being conducted at 100 research sites across the United States. The first patient was dosed at a site in Savannah, Georgia. About 30,000 healthy adult volunteers are expected to participate in the trial.
Volunteers receive either two 100 microgram injections of the vaccine or a placebo about 28 days apart. Neither participants nor investigators will know who has received the vaccine compared to the placebo.
The ultimate goal of Moderna’s Phase 3 trial is to determine if the vaccine can prevent symptomatic COVID-19 after two doses. Researchers will all study the data to find whether mRNA-1273 can prevent severe COVID-19 or laboratory confirmed SARS-CoV-2 infection with or without disease symptoms.
According to reports in early October, at least three patients who may have received Moderna’s experimental vaccine also experienced intense side effects like fever and chills. The symptoms also dissipate after only a day, and the volunteers reported returning to full health thereafter.
Though no pharmaceutical company has yet to complete a full series of clinical trials or be approved by a major regulator, both Pfizer and Moderna are eagerly eying the finish line.