Russell Kohl, MD, FAAFP
Chief Medical Officer at TMF Health Quality Institute
Clifford Moy, MD
Behavioral Health Medical Director at TMF Health Quality Institute
The delta variant of the SARS-CoV-2 virus has quickly become the predominant strain of COVID-19 cases in the United States, accounting for more than 80% of all new cases and almost all hospitalizations. During this surge, unvaccinated individuals, including younger adults and children, are experiencing more severe illness than in the past 18 months, with much higher rates of hospitalization and respiratory support requirements. The delta variant was first identified in India in October 2020. It is up to 60% more easily spread than the alpha variant, which was around 50% more transmissible than the original strain of the virus. As physicians, we’d like to take the opportunity to answer a few of the questions we’ve heard over the past few weeks.
How does the virus that causes COVID-19 keep mutating?
"Unvaccinated individuals reproduce the virus at a greater rate than vaccinated individuals, so they present the virus more opportunities to mutate during replication, leading to even more opportunities to create more dangerous variants."
COVID-19 is part of a family of viruses known as coronaviruses, which led to previous outbreaks such as MERS (Middle East Respiratory Syndrome) and SARS (severe acute respiratory syndrome). Viruses are not living organisms, like bacteria and human beings. Instead, viruses depend on the host cells that they infect in order to reproduce. This reproduction process of the virus’ genetic material within host animals, including humans, is frequently associated with “transcription errors” that can lead to the development of mutations. When these mutations prove to be advantageous for spread or reproduction of the virus, or they allow the virus to evade the host’s immune system, they duplicate more often and become a new variant copy of the original virus. The current delta variant is a mutation of the virus’ spike protein. This is the protein the virus uses to attach to human cells to start the infection process. This makes it more efficient at entering human cells and replicating at a greater rate. This allows humans to be both more easily infected and to produce more copies of the virus that will reproduce in their body, which leads to greater disease and greater ability to shed the virus in a way that infects other nearby people. Unvaccinated individuals reproduce the virus at a greater rate than vaccinated individuals, so they present the virus more opportunities to mutate during replication, leading to even more opportunities to create more dangerous variants.
Why does the vaccine affect how sick an individual becomes and how likely they are to spread the virus?
"The vaccine helps your body identify specific components of the virus to respond to, like memorizing the questions to the test, including the correct answers. "
Think of an infection as a test of your immune system, and the vaccine as looking at the test in advance. The vaccine helps your body identify specific components of the virus to respond to, like memorizing the questions to the test, including the correct answers. When infected, your immune system immediately recognizes the question and responds with the correct answer. An unvaccinated person might also get to the right answer, but it will take their immune systems time to “think” about the problem and solution. During that time, the virus is already replicating. The more antibodies you can produce against the virus, compared to the number of viral particles in your body, the less sick you become. While a vaccinated person starts immediately producing antibodies as soon as the virus enters the body, the immune system of an unvaccinated person has to recognize that there’s a virus, create a blueprint to fight it, then begin producing those antibodies. The immune system still works, but the virus is given a dramatic head start in the race to illness.
Why are unvaccinated individuals more susceptible to this delta variant and why are vaccinated people getting it?
The current COVID-19 surge is being called “the pandemic of the unvaccinated.” As we discussed above, the delta variant is able to reproduce significantly faster than the original strains of the virus and more easily enter human cells. The result is that the viral load in a patient increases rapidly at the beginning of the infection. While the immune system of vaccinated individuals can respond immediately, most unvaccinated are not able to create a rapid enough immune response to prevent illness. Some vaccinated individuals are also unable to rapidly make antibodies due to other medical conditions, and subsequently develop symptoms of infection. However, observations across the country have demonstrated that vaccinated individuals have largely been able to develop enough of a response that their illness is generally mild and not requiring of hospital-level care. At this time, over 90% of currently hospitalized individuals nationwide have not received the vaccine.
Why hasn’t the Food and Drug Administration fully approved the vaccines?
The Food and Drug Administration (FDA) approval process is not an emergency responsive program. It has a variety of requirements regarding both the studies submitted and the follow-up timelines required. In times of crisis, like a pandemic, the FDA is able to grant vaccines Emergency Use Authorization, but only after sufficient trials have been conducted to demonstrate that the vaccine is safe and effective. Each of the three vaccines on the market in the U.S. (Pfizer, Moderna, and Johnson and Johnson) have received an Emergency Use Authorization and have subsequently requested full FDA approval. Pfizer applied for full FDA approval in May 2021, and the FDA is expected to award approval late summer/early fall of 2021. Ongoing monitoring of the vaccines and any potential side effects has been accomplished via multiple systems and the real-time results are available online to the public through the Vaccine Adverse Events Reporting System (VAERS). Given the number of vaccines administered, there is strong statistical power to validate the safety and efficacy of each of the vaccines. As with all medical treatments, the FDA, physicians, and medical scientists will continue monitor the vaccines and report any potential concerns or findings.
What can we do to reduce infections and hospitalizations?
The reduction of infections and hospitalizations comes from a simple process, prevent the virus from entering human hosts, immediately neutralize its ability to reproduce when it does and prevent infected hosts from shedding the virus onto additional individuals. These are accomplished via the things we have been doing for the last year and a half: wearing masks, social distancing and washing our hands to prevent the spread between individuals, as well as getting vaccinated against COVID-19 to neutralize the impact of the virus in the event it enters a human host. The most important of these is to fully vaccinate as much of the population as possible, as quickly as possible, to reduce both illness to individuals and the ability of the virus to have large numbers of people to mutate within.
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Visit the Centers for Disease Control and Prevention’s Frequently Asked Questions page for information about COVID-19 vaccinations.