It’s been nearly two months since the first COVID-19 vaccine received emergency use authorization from the Federal Drug Administration. More than one million doses have been given in Illinois, including more than 15,000 in McLean County.
But those who study vaccines and infectious diseases are still bombarded with questions about how the shots work and what risks are involved.
Dr. Heather Zwickey chairs the Health Science Department and leads research at the National College of Natural Medicine in Portland, Oregon. Zwickey recently gave a lecture on COVID immunity as part of Illinois State University’s International Seminar Series.
Zwickey said most concerns over COVID vaccines are driven by fear of the unknown—but not from the scientific community.
“I know there's a lot of fear that these (mRNA) vaccines are ‘new to the market.’ They're new to the vaccine market for infectious disease, but we've actually been using them on cancers for 25 years,” Zwickey said. “Scientists know how to use them and know how to make them. It's just that we haven't used them for any of our childhood infectious diseases because we already have effective vaccines for those.”
Different types of vaccines
Zwickey said the vaccines most Americans are accustomed to—like for mumps, MMR, rubella, measles and chickenpox—take a different approach to stimulating an immune response. Those are all attenuated vaccines in which a live microbe through several species creates a weakened form of the pathogen.
Zwickey said attenuated vaccines are one of the strongest forms available. They provide vigorous immunity, she said, but that also means they tend to have the strongest side effects. The other concern is they can revert to an active form of the pathogen, she said, adding that’s what happened with the attenuated polio vaccine.
There also are recombinant or subunit vaccines that provide synthesized versions of proteins from the pathogen. Zwickey said that includes the flu shot, hepatitis B, human papillomavirus (HPV), pertussis, pneumococcal and meningococcal vaccines. She said the disadvantage of the recombinant or subunit vaccines is they're not very immunogenic, so they often require adjuvants—in many cases aluminum—and booster shots.
While both of the COVID vaccines currently available are mRNA vaccines, others in development are using other methods. Zwickey said there are around 90 coronavirus vaccines in development globally, with about 20 being worked on in the U.S.
“AstraZeneca and Johnson & Johnson are releasing the first recombinant vector vaccines for COVID, where they have put the spike protein for SARS COVID into an adenovirus—and an adenovirus is just a common cold virus,” Zwickey said. “The disadvantage is that adding the protein can promote significant changes in the adenovirus, or whatever that less pathogenic microbe is. So the safety studies are more intense than what we see happening with the mRNA vaccines.”
Zwickey said the attenuated and the vectored vaccines are likely going to generate the best immune response, based on past data. But they’re also the vaccines most likely to generate side effects, she said—and if they do generate side effects, they could be lung-related.
Meanwhile, subunit vaccines could come to market around May. Zwickey said those will be the safest for people with high-risk autoimmune diseases who may experience a flare due to the strong immune response triggered by attenuated and mRNA vaccines.
But for the vast majority of people, she said, any shot will do.
Infertility
Zwickey said the one of the questions she hears most often is if taking a COVID vaccine will affect a woman’s ability to get pregnant or have a healthy pregnancy. The short answer: no.
She said misinformation about infertility caused by the vaccines are percolated through social media. These claims trace back to a former Pfizer employee from Germany who partnered with an outspoken anti-vaccination epidemiologist to ask the European Medicines Agency to delay the study and approval of the vaccine.
They argued it would cause the body to make antibodies against a protein called syncytin-1. It’s an important part of the placenta in mammals and shares similar genetic instructions with part of the spike of the novel coronavirus.
The idea, Zwickey explained, was that the antibodies prompted by the vaccine would cause the mother’s body to reject the placenta.
“There's a lot of reasons why we don't think that is true,” she said, “The first is that the sequence of the peptide is so short that we're not seeing any antibodies form to it. And we're not seeing any antibodies that bind to placenta. Secondly, 44,000 women gave birth during COVID. With COVID. Their children were often born with (the) virus, but none of them rejected their placenta.”
However, Zwickey said, a study from the medical journal The Lancet shows roughly 30% of males who get COVID have at least temporary infertility because some ACE2 receptors, which allow the virus to bind to cells, are located in the testicles. Zwickey said that can reduce sperm count.
“So, for couples trying to conceive, we’ve got to worry more about the males who get COVID than the females who are vaccinated,” she said.
Others risks
Zwickey said the second most common question is: what about allergic reactions? Those concerns are somewhat overblown, she said, as only a small portion of recipients have needed to use an epipen after receiving the shot.
“It's roughly 2.5 people per one million vaccinated,” Zwickey said. “Now when we're vaccinating 100 million people, that's still a lot of people. But people are keeping epipens at the ready in case the unicorn comes in who has an allergic reaction with vaccine side effects.”
Zwickey said vaccine manufacturers and the people administering the doses are aware of the potential for an allergic reaction and are prepared to handle it, if it occurs.
Others are hesitant because of what they perceive as accelerated trials to get vaccines to market. But Zwickey said the standards of safety weren’t lowered. The major difference was that different stages of the trials happened at the same time, rather than in progressing order.
“The only risk in running those trials concurrently is that you may discover that there's an ineffective vaccine that you've now moved into phase two and and phase three,” Zwickey said. “There's not a great risk. It's more a financial risk than anything that you could move a vaccine forward (without effectiveness). You still wouldn't move it into the general public if it didn't work.”
Zwickey also rejected the idea that vaccine producers aren’t being transparent about what’s in the doses. She said the biggest hang-up has been the fat, or liposome, that surrounds the mRNA sequence.
“Some of the liposome content is proprietary,” Zwickey said. “That is not to say that Pfizer and Moderna have not listed every component of the vaccine. It's just one of the lipids that they've used is a manufactured lipid as opposed to a natural lipid. The reason for that is we live in a capitalistic society. They have to have something proprietary so that they can put a patent on their vaccine and make money with it.”
Herd immunity
Another common question: can’t I just wait to contract the virus and develop natural antibodies?
Infectious disease experts contend herd immunity can be reached once 70% to 80% of the population has antibodies to the novel coronavirus—preferably through vaccination.
Zwickey said the “natural” route is not as easy as getting an infection for a few weeks and then it’s gone. She said COVID can have long-lasting and seriously detrimental effects on a person’s health.
“We're seeing—even in people who did not have severe infections—lasting damage to the heart muscle,” Zwickey said. “We're seeing strokes and seizures. We're seeing scar tissue from the pneumonia. People having long-term lung issues. We've got people having microclots in their liver and their kidneys.”
That’s on top of other conditions like long-term fatigue syndrome, depression, anxiety and post-traumatic stress disorder—even in young people who contract the virus, she said.
“That's why we don't just encourage everybody to go out and get their herd immunity and just get this infection and get it over with,” Zwickey said. “Because the long term sequelae are far more severe than if you just got the flu (or even) if you just got the measles.”
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