Understanding the COVID-19 Vaccines
Photo by Joel Saget
Over a year ago, all of our lives were changed forever. This pandemic has challenged everyone in ways that we never thought possible. But there is finally a light at the end of this seemingly unending dark tunnel —the vaccines. With more and more people getting vaccinated every day, there is hope that we can get back to some semblance of normalcy.
Getting vaccinated is one of many steps we can take to protect ourselves and others from COVID-19. Protection from the virus is crucial because, for some people, it can cause severe illness or death. When it comes to comparing the three vaccines, the best one to get is the available one. There is no need to wait for a specific brand because all are currently authorized and recommended by the CDC. COVID-19 vaccines are safe, effective, and reduce your risk of getting critically ill.
Understanding How the COVID-19 Vaccines Work:
The vaccines help our bodies develop immunity to the virus that causes COVID-19 without us having to get the illness. To fully understand how vaccines work, it’s helpful to first look at how our bodies fight illness in general.
Germs, such as the virus that causes COVID-19, invade our bodies and attack and multiply. This invasion is known as an infection, which causes illness. Our immune systems use several tools to fight infection. Blood contains red cells, which carry oxygen to tissues and organs, and white or immune cells, which fight infection.
When a person is initially exposed to the virus that causes COVID-19, it can take several days or weeks for their body to make and use all the germ-fighting tools needed to beat the infection. When the infection passes, the person’s immune system will remember what it learned about how to protect the body against that disease.
The body keeps a few T-lymphocytes, called “memory cells”, that spring into action if the body encounters the same virus again. When the familiar antigens are detected, B-lymphocytes produce antibodies to attack them. It is still unknown how long these memory cells protect a person against COVID-19.
The Different Types of COVID-19 Vaccines:
Typically, it takes a few weeks post-vaccination for the body to produce T-lymphocytes and B-lymphocytes. So it’s possible that someone could be infected with the virus just before or just after vaccination, and then get sick because the vaccine did not have enough time to provide protection. The process of building immunity can cause symptoms, such as fever, but these symptoms are normal and are signs that the body is building immunity.
How they work:
Dado Ruvic/Reuters
This is a messenger RNA (mRNA) vaccine, which uses relatively new technology. “Other vaccines put a weakened or inactivated disease germ into the body, but “the Pfizer-BioNTech vaccine delivers a tiny piece of genetic code from the SARS CoV-2 virus to host cells in the body, essentially giving those cells instructions, or blueprints, for making copies of spike proteins (the spikes you see sticking out of the coronavirus in pictures online and on TV). The spikes do the work of penetrating and infecting host cells. These proteins stimulate an immune response, producing antibodies and developing memory cells that will recognize and respond if the body is infected with the actual virus.”
The Pfizer vaccine has been 95% effective in preventing COVID-19 in those without prior infection. Research shows that the vaccine has been equally successful across a variety of different types of people and variables, including age, gender, race, ethnicity, and body mass index (BMI)—or presence of other medical conditions. In clinical trials, the vaccine was 100% effective at preventing severe disease. Each dose of Pfizer contains 30 micrograms of the vaccine.
Dado Ruvic/Reuters
Like the Pfizer vaccine, this is an mRNA that sends the body’s cells instructions for making a spike protein that will train the immune system to recognize it. The immune system then attacks the spike protein the next time it sees one (attached to a real SARS CoV-2 virus).
This vaccine is 94.1% effective at preventing symptomatic infection in people who have not been exposed to the COVID-19 infection. The vaccine has also had high efficacy in clinical trials among people of diverse age, sex, race, and ethnicity categories and among persons with underlying medical conditions (although as mentioned above, the efficacy rate drops to 86.4% for people ages 65 and older). In late March, a small CDC study showed the vaccine to be 90% effective upon full immunization (at least 14 days after the second dose) in real-world conditions.
Each dose of Moderna contains a much larger dose of vaccine, 100 micrograms. This means that the company is using a little over three times as much vaccine per person as Pfizer is. And yet, they aren’t getting better results. The government’s vaccine development program, formerly called Operation Warp Speed, has asked Moderna to test if it could lower the dosage of its vaccine without eroding the vaccine’s protection.
Dado Ruvic/Reuters
This is a carrier vaccine, which uses a different approach than the mRNA vaccines to instruct human cells to make the SARS CoV-2 spike protein. Scientists have engineered a harmless adenovirus (a common virus that, when not inactivated, can cause colds, bronchitis, and other illnesses) as a shell to carry genetic code on the spike proteins to the cells (similar to a Trojan Horse). The shell and the code can’t make you sick, but once the code is inside the cells, the cells produce a spike protein to train the body’s immune system, which creates antibodies and memory cells to protect against an actual SARS-CoV-2 infection.
The FDA initially granted emergency use authorization to the Johnson & Johnson (J&J) vaccine in late February. Many experts were excited about the single-dose vaccine because it is easier to deliver and distribute, and played a crucial role in the global Covid-19 fight. But the distribution of the vaccine was paused due to its potential links to rare blood clots.
At the beginning of April, six reports of rare blood clots that were possibly linked to the vaccine prompted the FDA and CDC to call for states to halt the distribution of the vaccine. During that time researchers studied these rare cases of blood clots — which have occurred six times out of approximately seven million doses administered — could be linked to the vaccine.
After a thorough safety review, including two meetings of the CDC’s Advisory Committee on Immunization Practices, the U.S. Food and Drug Administration and the U.S. Centers for Disease Control and Prevention determined that the pause of the J&J vaccine in the U.S. should be lifted and distribution should resume.
Two Shots: Pfizer-BioNTech or Moderna, require more than one shot, and you aren’t considered fully vaccinated until two weeks after the second shot. The interval between Moderna doses is 28 days; for the Pfizer vaccine, it’s 21 days.
One Shot: Johnson & Johnson’s Janssen only requires one shot, and you are considered fully vaccinated two weeks after your shot. If it has been less than two weeks since your shot, or if you still need to get your second shot, you are NOT fully protected. It is crucial to keep taking all prevention steps until you are fully vaccinated.
All three vaccines have very similar symptoms:
In the arm where you got the shot
Pain
Redness
Swelling
Throughout the rest of your body
Tiredness
Headache
Muscle pain
Chills
Fever
Nausea
These side effects usually set in within a day or two of getting the vaccine and might affect your ability to do daily activities, but they should go away in a few days.
The Bottom Line
Getting vaccinated against COVID-19 and following the CDC’s recommendations to protect yourself and others will offer the best protection from the virus. People who have been fully vaccinated can start to do some things that we had stopped doing because of the pandemic.
But we’re not in the clear yet. Experts are still learning how vaccines will affect the spread of COVID-19. So even if you’ve been fully vaccinated against the virus, you should keep taking precautions in public places or when you are with unvaccinated people from more than one household who have been fully vaccinated.
