Here are answers to frequently asked questions about the coronavirus, the Covid-19 disease and the vaccines

MedPage Today illustration

This story has been updated.

By Melissa Patrick
Kentucky Health News

One of the many challenges facing Kentuckians who remain unvaccinated against the coronavirus is that they still have unanswered questions about vaccines, some based on facts and others based on myths. This story is an attempt to sort through some of those questions and to counter misinformation. 

This information is not only for the unvaccinated. Kentucky Health News encourages individuals who have already been vaccinated to use it as a resource when talking to their loved ones about getting vaccinated, since friends and family have proven to be highly influential in persuading them to do so.  

Covid-19 is no worse than the seasonal flu, right? Wrong. While influenza and Covid-19 are both contagious respiratory illnesses, they are caused by different viruses. Covid-19 appears to be more contagious and to spread more quickly, and is more deadly. Preliminary estimates from the Centers for Disease Control and Prevention are that the U.S. had 35 million flu cases and 20,000 deaths from it in the 2019-20 flu season, for a death rate of 0.06 percent. The U.S. has had more than 79 million confirmed cases of the coronavirus and over 977,000 deaths from Covid-19. In Kentucky, there have been over 1 million cases and more than 14,000 deaths. 

Kids don't get it, do they? Yes, they do. Children can be infected with the virus, and can get sick from Covid-19 and spread the virus to others without knowing they have it. In Kentucky, more than one-fifth of cases have been in people under 20. Most children have mild symptoms or no symptoms, but some have become severely ill from the disease and some have died. They can also get a rare but serious condition, Multisystem Inflammatory Syndrome, that sometimes doesn't show up until weeks after the infection. Kentucky has had more than 100 reported cases, according to the CDC. The more contagious Omicron variant of the virus that recently became dominant seems to affect them more.

These vaccines were developed very quickly; how can we be sure that they have been fully researched and proven? The vaccines were developed, tested and given emergency-use authorization in less than a year, thanks to years of previous research on related coronaviruses. Researchers had also been working on the technology for years; the timing, and federal funding by Congress and the Trump administration allowed companies to run multiple trials at the same time, saving time. Surgeon General Vivek Murthy said, "There were no corners cut in making these vaccines; what was cut was actually red tape."

Chart from University of Kentucky College of Medicine; for a larger version, click on it.

Why does it take so long for a drug to get final approval?  There has always been a long, deliberate process at the Food and Drug Administration to fully approve a drug, involving a review of much more data over a longer time than is required for emergency use authorization. 

The Pfizer-BioNTech Covid-19 vaccine was fully approved in August and the Moderna Covid-19 vaccine gained full approval for people ages 18 and older on Jan. 31. Both drugs were first approved under an emergency use authorization.

Does this new type of vaccine change your DNA? "Covid-19 vaccines do not change or interact with your DNA in any way," the CDC says. The new types of vaccines deliver instructions "to our cells to start building protection against the virus that causes Covid-19." Johns Hopkins University says, "The messenger RNA from two of the first types of Covid-19 vaccines does enter cells, but not the nucleus of the cells where DNA resides. The mRNA does its job to cause the cell to make protein to stimulate the immune system, and then it quickly breaks down — without affecting your DNA." 

What are the issues with the Johnson & Johnson vaccine? Is it still recommended? In April 2021, the J & J (Janssen) single-dose vaccine was paused while the FDA and the CDC investigated a very small number of cases of blood clots in people who had received it, nearly all of them adult women younger than 50. The FDA and CDC recommended that administration of the vaccine could safely resume. After more than 18.5 million doses of the vaccine had been given in the U.S. there were 60 confirmed reports of people who got the vaccine later developing blood clots, according to the CDC. 

On Dec. 16, the CDC recommended that people shouldn't get the J & J vaccine when the Pfizer-BioNTech and Moderna vaccines are available. The CDC news release said, "Any vaccine is better than being unvaccinated." 

In July, the Food and Drug Administration added a new warning about the J & J vaccine because it was linked to a rare neurological condition, Guillain-Barré syndrome. Preliminary research reported in July found 100 Americans out of more than 12 million who had developed the syndrome after receiving the vaccine; one died and 95 were hospitalized. The FDA said in a news release that “the known and potential benefits” of the vaccine “clearly outweigh the known and potential risks.” Through March 24, there have been around 310 preliminary reports of Guillain-Barre syndrome out of more than 18.5 million J&J vaccine doses administered, according to the CDC. These cases have largely been reported about two weeks after vaccination and mostly in men, many 50 years and older. 

"In most situations, Pfizer-BioNTech or Moderna Covid-19 vaccines are preferred over the J&J/Janssen Covid-19 vaccine for primary and booster vaccination due to the risk of serious adverse events," says the CDC.

What are the side effects of a Covid-19 vaccination? The most common side effects are pain, redness and swelling on the arm where you get the shot. Other side effects are tiredness, headache, muscle pain, chills, fever and nausea. Side effects after a second shot may be more intense. There have been three confirmed cases of the rare blood clot following the Moderna vaccine and one after the Pfizer-BioNTech, out of 540 million doses of mRNA Covid-19 vaccines.

Serious adverse reactions after a coronavirus vaccination are rare, says the CDC. Anaphylaxis, which can occur after any vaccination, is severe and has occurred in approximately five people per million vaccinated in the U.S. Clinics keep people 15 minutes after a shot to make sure they don't have a reaction.

As of March 24, there have been 2,323 preliminary reports of myocarditis and pericarditis among people 30 and younger who received a coronavirus vaccine. Most cases have followed the Pfizer or Moderna vaccine, particularly in male teenagers and young adults. The CDC has confirmed 1,396 of the preliminary cases.

A recent study, published in JAMA Network, found that "passive surveillance" reporting in the U.S. showed an increased risk of myocarditis after receiving either Pfizer or Moderna Covid-19 vaccine, the mRNA-based vaccines. The risk was highest after the second vaccine dose in adolescent males and young men under the age of 25. The heart condition is treatable.

The study notes that among more than 192 million persons older than 12 receiving more than 354 million mRNA-based Covid-19 vaccines during the study period, there were 1,991 reports of myocarditis, with 1,626 of them meeting the case definition of the disease.

"Among persons younger than 30 years of age, there were no confirmed cases of myocarditis in those who died after mRNA-based Covid-19 vaccination without another identifiable cause and there was 1 probable case of myocarditis but there was insufficient information available for a thorough investigation," says the report.

The report concludes that while this is a "rare but serious adverse event" than can occur after taking these vaccines, "This risk should be considered in the context of the benefits of Covid-19 vaccination."

Do I need a shot if I've already had the virus? The CDC recommends that those who have been infected with the virus should be vaccinated, because we don't know how long or strong the resulting immunity is. "Emerging evidence shows that getting a Covid-19 vaccine after you recover from Covid-19 infection provides added protection to your immune system. One study showed that, for people who already had Covid-19, those who do not get vaccinated after their recovery are more than two times as likely to get Covid-19 again than those who get fully vaccinated," says the CDC. If you were treated for Covid-19 with monoclonal antibodies or convalescent plasma, wait 90 days before getting a vaccine.

While "evidence is growing" that infection with the virus "is generally as effective as vaccination at stimulating your immune system to prevent the disease . . . federal officials have been reluctant to recognize any equivalency, citing the wide variation in Covid patients' immune response to infection," Kaiser Health News reports.

I got fully immunized, but then got infected. How did that happen? No vaccine is 100% effective, health officials say. The Pfizer and Moderna vaccines are about 95% effective in preventing Covid-19 in those without prior infections. The Johnson & Johnson vaccine has a 72% overall efficacy rate and an 86% efficacy against severe disease in the U.S. 

What's the latest information on who needs a booster? Research has found that a booster shot of the Pfizer-BioNTech or Moderna vaccine is needed to protect against the highly contagious Omicron variant of the virus. 

However, a CDC study published Feb. 11 found that booster shots of the Pfizer-BioNTech and Moderna vaccines are highly effective against moderate and severe Covid-19 for about two months after a third dose, but lose substantial effectiveness after about four months, suggesting the need for additional boosters. 

The study found the vaccine was 91% effective in preventing hospitalization during the two months after getting the shot, but fell to 78% effective after four months. Vaccine effectiveness against Covid-19 associated emergency department or urgent care visits also dropped over time, falling from 87% in the first two months to 66% after four months. After more than five months, vaccine effectiveness fell to roughly 31%, although the researchers note that there was little data available for this group of people

Adults 18 years and older can get any of the Covid-19 vaccines as a booster. A booster is recommended five months after the second shot for those who initially received a Pfizer-BioNTech or Moderna vaccine.  

The CDC  recommends 12-to-17-year-olds should get the Pfizer booster at least five months after their second Pfizer shot. 

Additionally, the CDC recommends that moderately or severely immunocompromised 5-11-year-olds receive a booster dose of vaccine 28 days after their second shot. 

Everyone who received the Johnson & Johnson (Janssen) vaccine is eligible for a booster shot at least two months after they get the single-dose vaccine. It is especially important for those who got the J&J vaccine to get a booster, since it has been shown to be less effective over time compared to the Pfizer and Moderna vaccines. The CDC recommends encourages those who got the J&J vaccine to get a Moderna or Pfizer booster in most situations. 

The latest guidance says people can receive a different brand of vaccine as a booster than they did their initial shots. 

Who needs a 3rd booster shot? The CDC recommends that certain immunocompromised individuals and people over the age of 50 who received their first Moderna or Pfizer Covid-19 booster shot at least four months ago to get another booster of either vaccine. 

CDC also recommends that adults who have received a one-dose J&J Covid-19 vaccine and a J&J booster at least four months ago may now receive a second Covid-19 booster of either the Moderna or Pfizer vaccine. 

This recommendation comes after the U.S. Food and Drug Administration authorized the second booster on March 29. 

"These updated recommendations acknowledge the increased risk of severe disease in certain populations including those who are elderly or over the age of 50 with multiple underlying conditions, along with the currently available data on vaccine and booster effectiveness," the agency said in a statement about the new recommendations. 

Children and Covid-19 vaccinations: Most children and all teens can get a Covid-19 vaccination. 

The Pfizer-BioNTech Covid-19 vaccine is approved for children 12 and older in the same dosage as adults, which comes in a purple capped vial. 

The Pfizer-BioNTech Covid-19 vaccine for children 5 to 11 is one-third of the adult dose and comes in an orange capped vial and is delivered with a smaller needle, designed specifically for children.  

Both of these vaccines require two doses, given three weeks apart. 

Why do I need to wear a mask if I've been vaccinated? Research indicates that vaccinated people who contract the highly contagious Omicron variant can spread it to others. The CDC advises universal masking for everyone indoors, regardless of vaccination status. Several studies show that properly wearing masks slows the spread of the virus, as part of a multi-layered prevention approach. 

The largest randomized controlled study of masks, led by researchers from Stanford and Yale universities, looked at the benefits of surgical-mask use by more than 342,000 adults in Bangladesh. It found that mask usage increased 29 percent in the intervention group where masks were promoted, and the group showed an 11% reduction in Covid-19 infections, with a 35% reduction among those over 60. The Washington Post reports that the study is under peer review with the journal Science.

Most recently, a CDC study, released Feb. 11, found that consistent use of a face mask or respirator (KN95 or N95) in indoor public settings was associated with lower odds of getting Covid-19. 

Among the 534 study participants who reported the type of mask they used, cloth masks offered 56% more protection against the virus than wearing no mask indoors; surgical masks offered 66% more; and respirator mask, such as N95 or KN95, offered the most additional protection, 83%.

Because of the highly contagious Omicron variant, public health experts say it is time to upgrade your  cloth mask to an N95 or similar high-filtration respirator when you are in public indoor spaces. 

Why are we hearing so much about the Omicron variant? It is now by far the dominant strain in the U.S. and Kentucky, and may be as contagious as measles, the most contagious virus known. 

Chart from UK College of Public Health; click it to enlarge.

While Omicron appears to be less severe overall than the Delta variant, it can still cause severe and even deadly infections in some people. And because it is so contagious, it has the potential to overwhelm Kentucky's health care systems.

People who are not fully vaccinated and boosted are most at risk from the Omicron variant. If a community has a low vaccination rate, that creates an opportunity for local outbreaks that have the potential to overwhelm the health-care system.

While two doses of the Pfizer or Moderna vaccine provides some protection against the Omicron variant, a booster vaccination has been found to ramp up this protection, particularly against severe illness and hospitalization. 

What do we know about the BA.2 Omicron subvariant? The highly contagious Omicron subvariant BA.2 is now the dominant coronavirus strain in the U.S, says the CDC. In the week ended March 26, the BA.2 variant caused more than half, 54%, of all new Covid-19 infections in the U.S, according to the CDC's genomic surveillance. The data shows only 1.5% of Kentucky cases are BA.2, but Gov. Andy Beshear has said it's likely closer to the national average. At this time, the BA.2 subvariant does not appear to make people sicker than the original Omicron. 

Can vaccines affect fertility? "The Covid-19 vaccine will not affect fertility," say physicians at Johns Hopkins University in Baltimore. They said the myth sprang from a false report on social media that the Pfizer and Moderna vaccines would affect not only the spike protein on the surface of the virus, but another spike protein that is involved in growth and attachment of the placenta in pregnancy. "The two spike proteins are completely different and distinct, and getting the Covid-19 vaccine will not affect the fertility of women who are seeking to become pregnant, including through in vitro fertilization methods," the doctors say. The CDC says, "There is currently no evidence that Covid-19 vaccination causes any problems with pregnancy, including the development of the placenta. In addition, there is no evidence that female or male fertility problems are a side effect of any vaccine, including Covid-19 vaccines."

What about microchips? There are no microchips or any kind of device in the vaccines, but this hasn't stopped about one in five people from thinking it's true. First and foremost, it is physically impossible; James Heathers of The Atlantic examined the notion in detail. A related myth is that the vaccine can make you magnetic. The CDC says, "Covid-19 vaccines do not contain ingredients that can produce an electromagnetic field at the site of your injection. All Covid-19 vaccines are free from metals." 

Where can I get more information? And how do I tell truth from deception? The Immunization Action Coalition provides a list of questions you should ask when evaluating health information online, such as the original source of the information and who manages it. The University of California-San Francisco offers tips on how to find credible sources of health information, including red flags to watch for, including outdated or anonymous information, possible conflicts of interest, one-sided or biased information, if there is a claim of a miracle or a secret cure, or if no evidence is cited.

Kentucky Health News is an independent news service of the Institute for Rural Journalism and Community Issues, based in the School of Journalism and Media at the University of Kentucky, with support from the Foundation for a Healthy Kentucky.