Your Guide To Adult Vaccines
En español | As the U.S. works to quickly roll out the new COVID-19 vaccines, the hope is that a critical mass of Americans will be vaccinated by this summer or fall so we can return to some semblance of normalcy.
However, the unprecedented speed of vaccine development and a surge of misinformation on social media has fueled skepticism about the vaccine among some Americans.
Public health experts emphasize that all COVID-19 vaccines authorized for emergency use in the U.S. went through the Food and Drug Administration's strict vaccine development time line, which includes three phases of clinical trials to generate information on safety and effectiveness and a review by an independent panel of scientists.
Here are some prevalent coronavirus vaccine myths and the truth behind each one.
Myth #1: If you've had COVID-19 already, you don't need to get vaccinated.
The Centers for Disease Control and Prevention (CDC) says it’s important to be vaccinated even if you already had COVID-19. That’s because experts don’t know how long you are protected from COVID-19 after a previous infection — or if you are protected at all.
“Even if you have already recovered from COVID-19, it is possible — although rare — that you could be infected with the virus that causes COVID-19 again,” the CDC says.
A study published in The Lancet on March 18 found that adults age 65 and older who have tested positive for the coronavirus are significantly more likely than younger people to be reinfected with the virus. The study, which looked at the testing data of four million people in Denmark, found that adults age 65 and older who had been previously infected had only about 47.1 percent protection against a repeat infection, compared to a protection rate of about 80 percent among younger people.
The difference can likely be explained by natural changes that weaken your immune system as you age, the study’s authors said.
Another study, published by the CDC in February, described five residents in a Kentucky nursing home who recovered from the coronavirus in July 2020 and then were reinfected three months later. The residents suffered more severe symptoms during their second bout with COVID-19, the report said, and one died of the disease.
The study suggests that people who show mild to no symptoms during their first infection “do not produce a sufficiently robust immune response to prevent reinfection,” the CDC researchers wrote. The study also raises “the possibility that disease can be more severe during a second infection,” they said.
If you had COVID-19 and you were treated with monoclonal antibodies or convalescent plasma, the CDC recommends waiting 90 days to get the vaccine.
Myth #2: Once you receive the coronavirus vaccine, you're immune for life.
Studies are underway to determine how long immunity from a coronavirus vaccine will last. But it’s likely you will need to get the shot on a regular basis, perhaps once every three years or every year like the flu shot.
That will allow scientists to adjust the formula, if necessary, as new strains, or variants, of the coronavirus emerge.
“Right now, everyone is hoping that immunity will be pretty long-lasting, maybe several years,” says Christopher Murray, M.D., director of the Institute for Health Metrics and Evaluation at the University of Washington in Seattle.
But he says the emergence of new strains of the virus, along with the prospect of waning immunity, make annual vaccination more likely.
Myth #3: You can ditch your mask after you get vaccinated.
It takes about two weeks after your final vaccination for your body to build full protection to the coronavirus. But even after those two weeks, the CDC says you should continue to wear a mask and practice social distancing in most situations.
That’s partly because researchers don’t know yet whether the vaccine can block virus transmission. That means it’s possible that you could still carry the virus once you’ve been vaccinated and silently transmit it to others, even if you don't have symptoms.
Perhaps more importantly, the virus will continue to spread and sicken people until the country reaches herd immunity, when 70 to 85 percent of Americans are vaccinated. Masks and social distancing are the best way to slow the spread of the virus until we reach that point, the CDC says.
The CDC says fully vaccinated people can gather indoors without wearing a mask or physically distancing when spending time with:
- Other people who are fully vaccinated
- Unvaccinated people from one other household, unless any of those people or anyone they live with is at increased risk for severe illness from COVID-19.
Myth #4: The vaccines use a live version of the coronavirus.
None of the authorized vaccines in the U.S. use the live virus that causes COVID-19, and they cannot give you the disease. Instead, the vaccines use scientific techniques to train the human body to recognize and fight the coronavirus.
The Pfizer-BioNTech and Moderna vaccines deliver a small fragment of genetic code to your cells to encourage your body to produce antibodies.
The J&J vaccine works differently. It uses a harmless adenovirus that can no longer replicate to send a genetic message to your cells.
While the coronavirus vaccines will not make you sick with COVID-19, they do cause side effects in some people. Commonly reported side effects include injection-site pain, fatigue, headache, chills, fever and muscle aches. Most of the reactions are temporary and resolve within a few days, according to the CDC. Experts stress that they are a sign the vaccines are working.
Myth #5: mRNA vaccines can alter your DNA.
COVID-19 vaccines do not change or your DNA, the CDC says.
The Pfizer-BioNTech and Moderna vaccines both use a new type of technology called messenger RNA, or mRNA for short. Think of mRNA as an instruction manual: It directs the body to build an immune response to a specific infection. The mRNA “never enters the nucleus of the cell, which is where our DNA are kept,” the CDC says. “This means the mRNA does not affect or interact with our DNA in any way.”
Johnson & Johnson’s COVID-19 vaccine uses a harmless virus (not a coronavirus) to deliver instructions to your cells to start building immunity. The instructions are delivered in the form of genetic material that does not integrate into your DNA, the CDC says.
The CDC stresses that authorized COVID-19 vaccines are being held to the same safety and effectiveness standards as other vaccines that are approved or authorized in the U.S.
Myth #6: You don't need both doses of the two-dose vaccines.
Both the Moderna and the Pfizer-BioNTech vaccines require two doses that are given a few weeks apart. And because health experts are not sure whether one dose will be sufficiently effective in preventing COVID-19 or a severe case of the illness, skipping the second shot is not a good idea. As the CDC explains: The first shot starts building protection while the second shot boosts that protection and “is needed to get the most protection the vaccine has to offer.”
A peer-reviewed analysis from Pfizer/BioNTech's phase 3 clinical trial found that its vaccine was about 52 percent effective after the first shot. After the second dose, the effectiveness jumped to 95 percent.
"We don't know what happens after a single dose,” William Moss, M.D., executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health, told AARP in a previous interview. “Certainly, we can't expect [that one dose will confer] the high degree of protection” that both doses demonstrated in phase 3 clinical trials, he added.
Myth #7: You shouldn’t get the vaccine if you’ve ever had an allergic reaction.
If you have a history of allergic reactions to oral medications, food, pets, insect stings, latex or things in the environment like pollen or dust, you can safely get the COVID-19 vaccine, the CDC says. You can also get the vaccines if you have an egg allergy, because none of the authorized vaccines contain eggs or egg-related components.
The only group the agency says should definitely abstain are those who have had a severe allergic reaction to any ingredient in a COVID-19 vaccine. If you’ve had an allergic reaction to other vaccines or to injectable medications, the CDC recommends talking to your medical provider about whether to get the vaccine.
Only a small number of the people who have received a COVID-19 vaccine so far experienced the severe allergic reaction called anaphylaxis. Anaphylaxis has affected about two to five people per million vaccinated, the CDC says. Although anaphylaxis is life-threatening, it almost always occurs within 30 minutes of vaccination and can be quickly halted with a medicine such as epinephrine. All of the patients who experienced anaphylaxis after a COVID-19 vaccination recovered, the CDC says.
The agency recommends that people with a history of anaphylaxis stay on site for observation for 30 minutes after vaccination. Those with no history of anaphylaxis should stay for 15 minutes.
This story has been updated to reflect new vaccine developments.