What You Need to Know About The Covid Vaccine

8 min readFeb 25, 2021

The Food and Drug Administration (FDA) of the U.S. has approved two vaccines for the SARS-CoV-2 virus (responsible for COVID-19) and countries around the world have begun vaccinating their populations. This means the pandemic finally has an end in sight! Once you’ve been vaccinated, however, it doesn’t mean you can start visiting your favorite restaurant for brunch with your besties or unmask at the barber shop. We haven’t collected enough evidence to support that a vaccinated individual can stop using social-distancing and other preventative measures. Life will continue as normal in the pandemic world — social-distanced and masked-up. Perhaps it’s confusing that, even after being vaccinated, you can’t return to the good ol’ days, so let’s try to clear that up in today’s blog.

Vaccines used in the U.S.

First, let’s give thanks to the many companies that worked tirelessly to bring us viable vaccines. There are several available vaccines produced by many different institutions that we won’t have time to cover here. The two we decided to focus on are Pfizer BioNTech and Moderna, as these are the first two vaccines the U.S. FDA has approved for use. Both are messenger RiboNucleic Acid (mRNA) vaccines that utilize a snippet of mRNA from SARS-CoV-2 (Covid virus) itself. This mRNA is translated by our body’s cellular machinery to create the viral spike protein that’s present on the surface of the virus- which is easily targeted by our immune system. After receiving the vaccine, our cells will take up the mRNA, translate it, and produce the spike protein. That’s when our adaptive immune system kicks in and starts creating antibodies to attack the foreign protein. The effective antibodies that were produced will be saved into our cellular “memory” and produced when the spike protein shows up in the future — say, if we contract COVID-19 [1, 2]. Check out our past blog on vaccines to understand them in greater detail.

The Pfizer BioNTech and Moderna vaccines are quite efficient at preparing our immune system for infection. They are the most efficacious at 95% and 94.1% respectively [3]. This doesn’t mean that 5% of people will still contract Covid after being vaccinated — not even close. What it means is that vaccinated people have a 95% lower risk of becoming symptomatic from Covid. To put this in perspective, you are 20 times less likely [4] to exhibit any COVID-19 symptoms once vaccinated than someone who is not vaccinated. Keep that wording in mind because we’re going to address it later.

Both vaccinations come in two rounds — the second dose being administered 3–4 weeks (depending on brand) after the first. In this case, the first dose works like we explained above — the immune system produces and saves effective antibodies — whereas the second dose improves the immune response. Your body will become more responsive to the spike protein when it appears to be a regular invader. When administering the second dose, the CDC suggests that individuals stick with the same vaccine, but other countries do not have this same guideline.

It’s common to experience side effects with any treatment and these vaccines are not an exception. Most people will exhibit one or more of the following side effects:

Local side effects that include pain, swelling, and lymphadenopathy (swelling of the lymph nodes in places like your armpit) at or near the injection site.
Systemic side effects like fever, fatigue, chills, etc. that about 75% of individuals will experience.

Side effects tend to be mild to moderate and occur within the first three days after being vaccinated. It’s normal to experience a more severe occurrence following the second dose and very few people (around 1%) have reactions more severe than moderate. These side effects may sound similar to the kinds of symptoms of being sick with a respiratory virus, and that’s because they are the consequence of your body learning to fight the infection. In the case of the vaccine though, these symptoms are generally a good indicator that your body is now prepared to fight the real virus and are not a bad sign.

Life After Vaccination

Once you have the vaccine, how does life change? Well, the CDC is constantly updating their guidelines on their site — it would be wise to bookmark it to stay up-to-date with recommendations. Currently, the CDC has not created separate guidelines for vaccinated individuals as there is “limited information on how much the vaccines prevent transmission and how long protection lasts.” The CDC continues to recommend preventative measures such as mask wearing and social distancing. What we do know is that symptomatic persons are at higher risk of transmission and the vaccine reduces or eliminates the symptoms entirely. Therefore, the likelihood of transmission is theoretically much lower from vaccinated individuals who become infected than from those that are not vaccinated. Actual rates of infection from vaccinated individuals are unknown and there are no studies that support this “reduced-threat” theory yet.

While there are no major changes in the guidelines, the CDC has recently stated that individuals who have been “fully vaccinated” (it has been at least 2 weeks since they have received their final dose) are no longer recommended to quarantine if they have been exposed to someone with COVID-19. In their update, the CDC stated, “vaccination has been demonstrated to prevent symptomatic COVID-19; symptomatic and pre-symptomatic transmission is thought to have a greater role in transmission than purely asymptomatic transmission”.

Dr. Anthony Fauci, the director of NIAID, has stated that he expects the CDC to soon release a new, relaxed set of COVID-19 guidelines for vaccinated individuals.

Preventative measures are likely to be the mainstay until enough of the population has been vaccinated to achieve herd immunity. Unfortunately, no one knows exactly what percentage of the population that is — initial estimates suggested between 60–70% of the population, that number has been revised upwards to between 70–90% [5]. Additionally, there are existing variants of Covid out there for which there is no efficacy data concerning the current vaccines.

Unanswered Questions and Tentative Answers

Vaccines can provide different forms of immunity from viruses. One form of immunity that could greatly impact the quality of life for vaccinated individuals is what is called sterilizing immunity. A person with sterilizing immunity is not only immune from symptoms of the virus, but also cannot spread the infection to anyone else. If it is the case that the existing Covid vaccines provide sterilizing immunity, that would mean that a successful vaccination would protect individuals from symptomatic and asymptomatic infection and protect them from infecting others. For these people, many protective measures such as mask wearing and social distancing would be redundant. However, the data on the types of immunity that the vaccines provide is still being collected, so we will have to wait to get confirmation on the presence or lack of sterilizing immunity.

Although both vaccines have passed through clinical trials, those trials aimed to identify two key attributes of the vaccines: (1) that they were safe to give to humans and (2) that they reduced the risk of symptoms, especially life threatening symptoms. Thus, the trial focused on identifying participants who displayed symptoms of COVID-19 rather than continuously testing all participants to identify asymptomatic infections. Since people with asymptomatic infections may still infect others, these clinical trials are not proof of sterilizing immunity.

There are currently studies underway to evaluate the ability of the vaccines in preventing asymptomatic infections. One published in The Lancet looked at infection rates of healthcare workers (HCWs) at Sheba Medical Center in Israel that were and were not vaccinated. The study shows that vaccinated individuals had a 75% lower likelihood of a SARS-CoV-2 infection and an 85% lower likelihood of displaying symptoms 2–3 weeks after a single dose [6]. There are ongoing serological follow-up studies to the clinical trials for the Pfizer and BioNTech vaccine that should investigate asymptomatic infections and other immune responses that are significant for achieving sterilizing immunity.

Several studies have been investigating the real-world impact of vaccination in Israel due to the high population-percentage that has already been vaccinated. There is one that investigated the difference in the amount of virus present (viral load) in positive tests (PCR Covid-19 tests) among Israelis aged 60 and older versus those aged between 40–60. Israel prioritized vaccination in those 60+, so they were the first to receive the vaccine and could identify the effect of population vaccination in viral load. Thus, answering the question of the level of immunity the vaccine provides. They found a dramatic reduction in viral load — up to 20 times lower [7]! This suggests that even if individuals contract Covid after vaccination, they are less likely to transmit the virus to others. This mirrors results from a similar study in Israel that looked specifically at individuals who were infected after vaccination [8].

Finally, A study in rhesus monkeys found that monkeys vaccinated with a high dose of the Moderna vaccine were much less likely to have any virus in their lungs after being intentionally exposed to SARS-CoV-2 through a nasal spray [9].

These studies are all excellent signs that the vaccines will reduce COVID-19 symptoms, assist the body in eliminating the virus, and prevent vaccinated individuals from infecting others! In all, things are looking good for the world. We have highly effective vaccines and a plan to exit the pandemic. At the same time, we don’t want to ignore the new Covid strains that exhibit greater contagion. Nor can we forget about the important unanswered questions. Keeping this in mind, it would be wise to observe the CDCs guidelines and get vaccinated as soon as you can. Until we hit herd immunity numbers, we have to keep the masks on, but once you’re vaccinated, you can start to relax. The Macromoltek team is rooting for a return of Sunday brunches, evenings at the theater, and pick-up basketball in the park.

Citations:

What You Need to Know About The Covid Vaccine

Vaccines used in the U.S.

Life After Vaccination

Unanswered Questions and Tentative Answers

Written by Macromoltek, Inc.