The FDA has now authorized three COVID-19 vaccines. Both of the first two authorized vaccines rely on an immunity-building strategy that hasn’t been used in any other vaccine. As many of us start rolling up our sleeves to get a shot, here are answers to some of the most frequently asked questions.
What is mRNA? Why does it matter?
All previous vaccines have been based on weakened virus molecules or proteins from the disease (pathogen) that our immune systems can easily overcome while learning to recognize it. The new vaccines from Moderna and Pfizer — the first two to make it to market so far in the U.S. — contain mRNA (messenger RNA), which is a genetic template that instructs our cells to build the viral proteins that our immune systems can then recognize. Its main perk is that by allowing our bodies to produce the proteins (rather than growing them in a lab like in traditional vaccines), it slashes the time it takes to produce the vaccine (as done in the past) in the lab. For nearly 20 years, researchers have been interested in using mRNA in vaccines. Some were even tested in early clinical trials for rabies, influenza and Zika. However, the vaccines for COVID-19 are the first mRNA vaccines ever authorized by the FDA. This long history of studying the mRNA concept is why the vaccine could be developed so quickly. mRNA is new to you and me, but a well-known process to scientists.
Will the COVID-19 vaccine change my DNA?
mRNA is a messenger in your body. It’s the way your DNA tells the rest of your body what proteins to create for various functions. In your body, mRNA is created in the nucleus of your cells, based on the DNA that resides there. Then the mRNA exits the nucleus to be used as a template for protein-making in the rest of the cell, and it has no way back in. Soon, it degrades without ever re-entering the nucleus or coming in contact with DNA. mRNA lives in the body between a few hours and a couple of days.
Like naturally occurring mRNA that has already left the nucleus of your cells, the mRNA vaccine isn’t able to enter your cell’s nucleus. Because of that process, it can’t come in contact with or change your DNA. Click here to see a video that explains the process more fully.
The Johnson & Johnson vaccine uses a viral vector — a harmless virus-turned-delivery system that’s been used in vaccines before — to introduce the gene that encodes a protein found on the surface of the COVID-19 virus. Our cells then create just this protein (not the whole COVID-19 virus) so our immune systems learn to recognize it. It also will not change your DNA.
Why do I need two shots of the Pfizer or Moderna vaccines?
Multiple doses of the vaccine expose our immune systems to more of the viral proteins, giving it the chance to develop more antibodies and protection. The immunity takes time to develop. Researchers believe that 10 days after the first dose, patients develop about immunity that is 52% effective. About a month after receiving their second dose, immunity can reach 94%. A similar strategy is used for other vaccines, like Shingrix, developed to prevent shingles.
Since the initial assessment, new analysis of the research suggests that two weeks after the injection, a single dose of Pfizer or Moderna’s vaccines is more protective than previously thought, potentially up to 92%.
How does the FDA decide if a side effect is severe?
The FDA has a toxicity grading scale to rate adverse events related to preventive vaccines. It ranks both local events (like injection site pain) and systemic events (like fever and nausea) as mild (Grade 1), moderate (Grade 2), severe (Grade 3) or life- threatening (Grade 4.) Several effects, like pain at the injection site, headache, fatigue and nausea, are considered Grade 1 if they do not interfere with your activity at all. If side effects do prevent you from doing ordinary tasks, they may be designated Grades 2 or 3. If the symptoms cause you to go to the emergency room for treatment, they are Grade 4.
Is the COVID-19 vaccine safe?
The most common side effects for all three vaccines — headache, fatigue, fever, chills and muscle and joint pain — are more intense than those for the flu, for example. And the side effects caused by the COVID-19 vaccine tend to be worse after the second shot than the first.
The FDA reported that up to 4.6% of Pfizer vaccine patients, 9.6% of Moderna’s patients, and 2% of Johnson & Johnson’s patients experienced severe (Grade 3) adverse effects. Grade 3 effects are those serious enough to interrupt a person’s life — for example, by causing them to take a day off of work — but not so severe that the person is hospitalized. Younger patients were more likely than older ones to experience severe adverse effects. No life-threatening effects were linked to the Pfizer vaccine and less than 0.1% of patients experience Grade 4 adverse effects to Moderna’s vaccine. Swelling, pain, rashes and redness at the injection site are common.
While some patients have experienced anaphylaxis, all have recovered.
Covid-19 vaccines have not been tested on pregnant or lactating women or on children. It also will need to be tested on millions of more people for scientists to understand how the vaccine may interact with certain chronic illnesses or other drugs.
Check out MedShadow’s vaccine side-effects tracker for more details.
How long were test patients followed and why?
The FDA required that patients in the Phase 3 trials be followed for a median of two months after the second shot before the data would be reviewed for its approval.
When it comes to side effects, the CDC considers vaccinations different from other medicines, because they aren’t taken continuously. In general, the CDC designates adverse events that happen within six weeks of administration to be potentially linked to vaccines. In the case of the Pfizer and Moderna vaccines, the mRNA is broken down within days of the injection, so it doesn’t remain in your body long term.
The CDC is tracking possible adverse reactions in early recipients through its V-safe app. The agency initially announced that it would follow these patients for six weeks but has since said it will check in on them at three months, six months and one year after receiving the vaccine. Individuals can also report adverse effects through VAERS, the government’s vaccine adverse event reporting system.
Who has been tested for the vaccine?
The vaccines have been authorized for adults. While Moderna’s and Johnson & Johnson’s vaccines have the okay for patients 18 and older, Pfizer’s original trial included a small number (163) of 16- and 17-year-olds and has been recommended for patients 16 and older. On March 31, the company announced that the vaccine was safe and effective for patients 12-15 years old.
The vaccines were effective in both men and women, regardless of weight or race. While Pfizer’s vaccine appears to be just as effective in older patients (65 and older) as in younger ones, Moderna’s vaccine offered slightly less protection (86% compared to 96%) in older patients versus younger ones.
None of the trials included pregnant or lactating women. Pfizer has started a trial in pregnant women and Johnson & Johnson says it plans to. While immuno-compromised people (such as those with the HIV, human immunodeficiency virus) were included in the trials, there isn’t enough information yet to determine if the vaccines offer different levels of protection to these groups.
A small study in pregnant and lactating women demonstrated that the Pfizer and Moderna vaccines were safe and led to a strong immune response in these patients. Additionally, the shots seemed to confer at least some immunity to the fetuses and newborns through placenta and breast milk. The study has not been peer reviewed, and is not as large as clinical trial.
Moderna and Pfizer are both currently testing their vaccines in younger teenage patients. Moderna announced it is starting a trial in patients as young as 6 months to 11 years old. Doctors have told the New York Times that side effects can be more intense in children than adults. The new trial will start with very low doses and increase them to find the lowest effective dose for children. The children will be followed for a full year.
Johnson and Johnson says it plans to test its vaccine in babies and children, pregnant and lactating women, and immunocompromised patients in upcoming trials.
Will the COVID-19 vaccine protect me from mutated versions of the virus?
Researchers have identified several mutated forms of the virus spreading in the UK, South Africa, Brazil, and elsewhere. Scientists believe the vaccines will still protect against these strains, but are running studies to confirm it. Moderna and Pfizer announced that their vaccine may offer slightly less protection against the variant from South Africa than it does to the variants originally tested. Johnson and Johnson also announced that their vaccine is less effective against this variant, but they believe it still prevents the most severe outcomes. Those in the study that did get the disease did not end up hospitalized.
Moderna is working on creating a “booster” shot that will offer greater protection.
“We’re doing it today to be ahead of the curve, should we need to,” Dr. Tal Zaks, Moderna’s chief medical officer, said in an interview cited in The New York Times in January. “I think of it as an insurance policy.”
“I don’t know if we need it, and I hope we don’t,” he added.
Can I Throw Away My Masks After I Get the Vaccine?
There are several reasons that you should continue to wear your mask and social distance after getting the vaccine. First, the clinical trials did not continuously test every participant for COVID-19; they only tested those patients who displayed symptoms. There is a chance that the vaccine protects people from getting sick, but not from contracting and spreading the virus without showing symptoms.No vaccine is 100% effective and it can be less effective especially in people with weakened immune systems. You’ll want to keep protecting those around you who are elderly, have cancer or other conditions that cause immunodeficiencies.
Nonetheless, the CDC announced guidelines suggesting that small groups of fully vaccinated people (people who received all doses of the vaccine more than two weeks ago) can now safely spend time together indoors without masks. These individuals should still wear masks in public spaces.
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