By Sarah Koch
As COVID-19 cases skyrocket in the United States, Americans anxiously wait for news of a readily available vaccine. All eyes are on Pfizer and Moderna, biotechnology companies that have recently reported promising results from COVID-19 vaccine trials. Neither vaccine has been approved by the FDA, but Pfizer submitted its request for emergency authorization on November 20th, and Moderna is not far behind. If approved, a vaccine could be available as early as mid-December. Keep reading for information about how these vaccines work, as well as an overview of what to expect for the future of each.
General Vaccine Information
When developing any vaccine, there are four phases of clinical trials that must occur before the FDA can approve it for widespread use. Both Pfizer and Moderna are still in Phase 3 of trials, but the results are promising. These companies are utilizing new vaccine technology that targets the messenger RNA, or mRNA, of cells. The vaccines use genetic code taken from the virus to build its “spike” protein which, when introduced to the body, teaches the immune system how to recognize and fight the virus. Although different methods have been used and about 10 other vaccines are currently in the running, Moderna and Pfizer have achieved the greatest success thus far using mRNA technology.
The FDA has announced a minimum 50% efficacy rate necessary for approval of a COVID-19 vaccine, but Pfizer and Moderna report results well above this. To put this number in perspective, the average flu vaccine has a success rate of around 40-60%, while two doses of a measles vaccine are found to be 97% effective. When a coronavirus vaccine is FDA-approved, it will be given first to frontline healthcare workers, then to high risk groups such as the elderly and immunocompromised, then to the general public.
Earlier this year, the federal government announced Operation Warp Speed, an effort to rapidly develop and distribute 300 million vaccine doses for COVID-19 before January 2021. Moderna has publicly received over $2 billion in federal funding through this program, while Pfizer opted to instead sell the government 100 million doses in advance for $1.95 billion upon receival.
The world breathed a sigh of relief on Monday, November 16th when Pfizer and its German counterpart BioNTech announced that their vaccine was more than 90% effective. This number has since been clarified to 95% for the general population, and 94% for older adults who are more vulnerable to COVID-19. Pfizer reports that, if FDA-approved, it could manufacture up to 40 million doses by the end of the year. Because the vaccine requires two doses—an initial and a booster three weeks later—this would be enough for up to 20 million Americans. By the end of 2021, Pfizer stated, it could distribute 1.3 billion doses, a promising number.
Pfizer has been testing its vaccine in Phase 3 of clinical trials. Double-blind trials have occurred with 44,000 volunteers; this means that neither the volunteers nor the doctors administering the vaccine know if the participants are receiving the actual vaccine or a placebo. So far in this trial, less than 200 cases of COVID-19 have occurred, most of which were from placebo recipients. Side effects including fatigue and headache have occurred, but both were fairly mild among volunteers.
The Pfizer vaccine is unique in that it must be stored at very low temperatures (approximately minus 94 degrees Fahrenheit). This has caused an increase in dry ice sales as the company tackles the distribution of doses. The Pfizer vaccine is expected to be approved and available before its Moderna counterpart, but because of the extreme cold requirements for storage, it will likely be limited to larger hospitals and universities, whereas the Moderna vaccine will likely be available at your local Walgreens and CVS.
The Moderna vaccine has also shown promising results in clinical trials as the Massachusetts-based company nears the end of its vaccine testing. More good news was announced on November 16th when a 94.5% efficacy rate was reported for the Moderna vaccine. This vaccine will also require two doses but with a slightly longer, four-week period between rounds. Moderna estimates that it can produce about 20 million doses before January if FDA-approved.
Moderna has also utilized double- blind trials for its vaccine testing. Preliminary results revealed that of the first 95 participants who got sick, 90 of them had received a placebo in place of the vaccine. The five who contracted COVID-19 did, however, only experience mild symptoms as opposed to the more severe responses seen in the placebo group. The vaccine’s 94.5% efficacy rate was based on this data and may be adjusted as trials continue.
Unlike the Pfizer vaccine, Moderna’s vaccine does not require extreme temperatures for storage. Instead, it can be kept at around minus 4 degrees Fahrenheit, or about the equivalent of a normal freezer. This increases the availability of the vaccine for companies and organizations that lack the resources needed to store Pfizer’s vaccine. Although the Pfizer vaccine is likely to be approved first, you can expect to see Moderna’s name at your local pharmacy sometime in 2021.
What does this mean for the future of COVID-19?
Although scientists are optimistic about the prospect of a vaccine, there is still a lot they don’t know, and the existence of a vaccine does not mean coronavirus is coming to an end. People still need to wear masks and practice social distancing; this includes limiting gatherings over the holidays. Unfortunately, this pandemic is probably going to get worse before it gets better. Major news sources and healthcare officials are urging America to prepare for a harsh winter. We must all do our part to keep ourselves and others safe as cases climb.