Experts weigh in on covid-19 vaccinations
With nearly 300,000 covid-19 vaccinations delivered so far, doctors and scientists say it will be months before Arkansans will be able to stop wearing masks, socially distancing and taking other preventive measures.
One reason, according to a leading state researcher, is that scientists are still studying whether those who receive the vaccine can transmit the coronavirus to others.
“That is still one of the unknowns,” Dr. Robert Hopkins, chairman of the National Vaccine Advisory Committee and professor of internal medicine at the University of Arkansas for Medical Sciences, said. “We are concerned about that being a possibility.”
And scant data exists on how long immunity lasts. Preliminary evidence suggests vaccines could build immunity to the coronavirus “for many, many months if not a year, or years,” Hopkins said, adding that it will take more time to determine how long an individual’s immune response lasts.
Even with the unknowns, public health experts say at least three-quarters of Americans will need to be vaccinated to achieve herd immunity before life can return to some semblance of normalcy.
“If we continue to do all of our other public health measures, along with the vaccine, maybe by this summer we can get enough people vaccinated that we can start backing [safety precautions] down,” Hopkins said. “At this point, the vaccine is one of a series of layers we are trying to use to protect ourselves.”
Here are more answers to common questions about the covid-19 vaccine, according to doctors, pharmacists and scientists interviewed by the Arkansas Democrat-Gazette.
Q. Is either vaccine now available, Pfizer/BioNTech or Moderna, better than the other?
A. In clinical trials, the Pfizer vaccine was 95% effective in preventing covid-19 in people who had not been previously infected; Moderna was 94.1%. Scientists say that amounts to virtually no difference.
The vaccines differ in transport and storage — the Pfizer brand must be kept at super-cold temperatures before it is thawed for use, for example. Still, the two vaccines function in much the same way.
The differences are “nothing that would really matter in your arm,” said Hopkins.
Q. After my shots, when am I protected?
A. Peak protection comes about two weeks after receiving the second dose, according to the federal Centers for Disease Control and Prevention (CDC).
Hopkins said he has encountered one patient who contracted an asymptomatic case of the coronavirus shortly after receiving the first dose of a vaccine. That likely occurred because the individual’s immune system had not had time to develop enough antibodies to fight it off, he said.
“I cannot think of anyone I have run into who has developed covid later than a week after that first dose of vaccine,” he said.
Q. What does “immunity” consist of?
A. It is unlikely people who have been vaccinated will develop a severe case of covid-19, or possibly even a symptomatic case. Unknown is whether they can be asymptomatic carriers and transmit the virus to others, according to the CDC.
“It is possible that an immunized person could still catch the virus and spread it to other people without getting sick themselves,” said Dr. Amanda Novack, Baptist Health’s medical director for infection prevention. “These are good vaccines, but not perfect, so even fully vaccinated people can still rarely get sick with the virus.”
One critical difference is that a vaccinated individual who contracts the virus would spread less infectious material, said Dr. Charles “Corey” Scott, a Little Rockbased emergency medicine physician and the 2019-20 president of the Arkansas Chapter of the American College of Emergency Physicians. Antibodies prevent a large amount of the virus from replicating inside the vaccinated person’s body, rendering it less contagious.
“It very likely won’t be as high a viral load because the antibodies are going to keep that virus from spreading gangbusters in your body,” Scott said. “Which means you won’t have as many virus parts, so it still decreases transmission regardless.”
Q. How long will I be immune from covid-19 after being fully vaccinated?
A. Despite preliminary studies suggesting immunity could last months or years, scientists don’t yet know.
“We won’t know how long immunity produced by vaccination lasts until we have more data on how well the vaccines work,” according to the CDC.
“We just have not had enough time yet to measure when [immunity] might go away,” Novack said via email. “We also do not know exactly how antibodies on a lab test correlate with protection in real life.”
Q. How many vaccinations will it take to achieve “herd immunity” and contain the virus?
A. A New York Times analysis estimated as of Saturday that 7.3% of Arkansans have gotten at least one vaccination so far, far short of the 75% experts say is needed.
Q. Should I worry that these vaccines were developed so quickly?
A. Historically, vaccine development has taken years. The covid-19 vaccines were created over months.
Health experts credit advancements in technology, in particular genetic sequencing, and also that coronaviruses are not new. Scientists have been studying these viruses for years after similar, yet smaller, epidemics broke out in China in 2002 and the Middle East in 2012.
Scientists “did try to make vaccines for a lot of these different diseases,” Scott said. But the diseases died out before vaccines could be created.
With covid-19, “it is much easier to do trials and tests because it is still out there and spreading so quickly,” Scott said.
Q.Will the shots alter my DNA?
A. “That is the biggest misconception we have handled,” said Daniel Cate, a pharmacist and co-owner of Marketplace Pharmacy in Little Rock, which has given out about 900 shots. “People ask, ‘Will this affect my DNA?’”
The vaccines are made of mRNA, or messenger ribonucleic acid, “which is a bit of coding that our cells will use to make a spike protein that looks just like part of the virus that causes covid,” according to Baptist Health’s Novack.
Because mRNA is fragile, it does not survive long in the body and has no effect on DNA, which is contained in a cell’s nucleus, Scott said.
Q. How does the vaccine work?
A. The mRNA in the vaccine provides cells with a set of instructions on how to make spike proteins that look like part of the coronavirus, which then appear on the surface of the cells.
The immune system then recognizes the spike proteins and starts to mount a defense against the foreign proteins, creating antibodies against covid-19.
“Your immune system remembers that virus, or at least that protein sequence that is on the virus,” Scott said. “If it sees that virus again, it ramps back up and makes more antibodies.”
That’s why it is crucial to get a vaccine, experts say.
Q. Why is covid-19 so deadly?
A. Human immune systems have never before encountered the virus, which has killed more than 4,800
Arkansans and more than 435,000 Americans.
Sometimes-overwhelming immune responses to the virus are what cause severe cases of covid-19, even death, Scott said.
“The vaccines give your body a head start on the infection versus just getting infected when your body does not have time to make antibodies fast enough,” Scott said. “It takes your body days to mount a response without any immunity.”
Q. Why can’t I start “normal life” as soon as I’m fully vaccinated?
A. Cate, the co-owner of Marketplace Pharmacy, said patients coming in for a shot often joke with him about returning to normal life. They talk about going on vacations, he said, or how soon they can stop wearing masks.
“People often joke around, like ‘we can go home and burn our masks, right?’” Cate said.
Jokes aside, public fatigue from wearing face coverings, socially distancing, staying home, avoiding parties and not taking vacations is real.
While the vaccines offer light at the end of the pandemic tunnel, experts say that until a large percentage of the population gets the shots, it is still too soon to stop taking precautions.
“The vaccine is an important tool in ending the pandemic, but vaccination alone will not eradicate the disease immediately,” Novack said. “Every time we prevent infection by vaccination, or masks or hand hygiene or social distancing, we get a step closer to a post-pandemic world.”