When Will a COVID-19 Vaccine End the Pandemic?
January 1, 2021
By Lisa Germain, DDS, MScD
As the end of 2020 fast approaches, the race to produce a Sars-Cov-2 vaccine appears to be sprinting around the last curve. With experts optimistic that the first one will be approved by the end of the year in the United States, the United Kingdom and Canada have already given approval for the vaccine produced by Pfizer called BNT162. There are 5 others that are currently in Phase 3 clinical trials. This means that the vaccines are being tested on large-scale populations between 30,000-60,000 people in double blind, placebo-based trials. This is the gold standard for clinical trials and is the key element to determine whether the vaccine is safe. While this is certainly good news, the global fight against Covid-19 still has some uphill battles to conquer before we can breathe comfortably (literally and figuratively) knowing that the pandemic is actually over. The recent uptick in cases of the virus, hospitalizations and deaths has many of us wondering if this will ever end.
While it is hard to look at the glass half full regarding anything that is related to the last 9 months, there actually is a silver lining for researchers. While most vaccines take years or even decades to develop, scientists had a huge head start because of their experience working with Sars-Cov-1 that, as luck would have it, has a striking family resemblance to Sars-Cov-2. Plus, the colossal impact of the pandemic has motivated the speed and the amount of funding surrounding the race for the “cure”. In addition, early access to the genetic sequence of the virus has facilitated the various biotech companies’ ability to string together the right pieces of the code to synthesize the vaccine, thus avoiding the timely process of obtaining the virus as well as the need to weaken or inactivate it.
Scientists immediately noted the similarity in the two viruses especially in the spike protein that was identified as a primary target for a vaccine. That knowledge combined with the use of lipid nanoparticles as a vehicle that facilitate mRNA from reaching its target without degrading, have been key elements in the fast tracking of a vaccine for Covid-19. While not all of the vaccines are using the mRNA model, the front-runners Pfizer BNT162 (in conjunction with BioNTech) and Moderna mRNA-1273 embraced this technology early on with astounding results.
The choice of the spike protein is based on the fact that this is the part of the virus that attaches to the human receptor cells, allowing it to enter the cells, replicate and ultimately cause infection. These spikes have also been identified as the most immune-sensitive feature of the virus hence if blocked from exposure could play the major role in disease prevention.
On December 1, 2020 The Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) made the decision to put health care providers and long-term care residents at the top of the priority list for the impending COVID-19 vaccines, once they are US Food and Drug Administration (FDA) approved. This group includes personnel who work in the following facilities including: hospitals, long-term care facilities, outpatient home health care, pharmacies, emergency medical personnel, and public health workers.
The unprecedented speed of development has made many of us skeptical about the safety and efficacy of the vaccine. However, there is an independent safety board that is responsible for monitoring the large populations in the trials for negative side effects. In addition, this board is tasked with determining the effectiveness of the vaccine by comparing the number of infections in the vaccine group with those of the placebo group. In November 2020, Moderna announced a 94.5% efficacy rate for their SARS-CoV-2 vaccine, while Pfizer announced a 95% efficacy rate for theirs. Both companies have applied for emergency use authorization from the FDA.
These two vaccines require 2 doses, the second one to be given 21 days after the first. The research has revealed that while antibodies began to develop in the first 7-10 days after the first injection giving reasonable protection, 95% efficacy was shown 7 days after the second injection. The results from phase 3 clinical trials also showed that it was effective for all ages tested, all ethnicities tested and appeared to ameliorate the severity of the disease even in patients with pre-existing co-morbid health issues. There is a warning that people who are “highly allergic” exercise caution and consult with their physician about the vaccination. There have been a few cases of anaphylactoid reactions reported by recipients of the Pfizer vaccine in the United Kingdom. However the use of an epi-pen mitigated the symptoms and they are all reported to be doing well.
Currently, it appears that the antibodies are protective for at least 6 months and probably longer, however the longevity of protection remains to be seen. While most diseases create a greater immunity than a vaccine, that is apparently not the case with Sars-Cov-2. It is recommended that even those who have developed natural immunity from having been infected in the past get vaccinated to create more and perhaps longer lasting antibodies.
Scientists also noted that once inoculated, you can become infectious for a period of time and care must be taken initially to prevent spread of infection to others.
All of this is good news, however, we are still a long way away from being able to go “maskless” in public. The enormous challenge to produce enough of the vaccine to immunize a global population of seven billion people is daunting. Because each person will need 2 shots, synthesizing, 14 billion doses along with the logistics of storing them in dry ice, shipping them and administering them, will take time. Like most things, however, we will need to keep taking this one step at a time. Even though the end is finally in sight, social distancing, and a face-mask are still de rigueur. Stay safe!!