Fear of the unknown with medicine is expected, but with a decision like whether or not to sign up for a COVID-19 vaccine, education is everything. Lisa Morici, Ph.D., associate professor in the Department of Microbiology and Immunology at Tulane University School of Medicine in New Orleans, Louisiana, cleared the air when she explained how COVID-19 vaccines work and dispelled some of the misinformation that has many afraid to be immunized.
According to Morici, traditional vaccines for viruses like the flu are one-drug-for-one-bug vaccines that consist of taking a virus and growing it in large batches, inactivating it so it cannot cause disease and injecting it as a vaccine. With some other established injections like the rubella vaccine, viruses are grown in large batches and weakened so they cannot cause a virus, but will induce a robust neuro response in the body.
However, the COVID-19 vaccines fall into two different categories: messenger RNA vaccines and adenovirus vector vaccines. These are both known as plug-and-play vaccines, which means the DNA or RNA from a vast number of germs can be “plugged” into the same vaccine platform, making them more versatile. The mRNA vaccines, which are the platforms the Pfizer and Moderna vaccines use, are the only vaccines currently authorized in the United States.
“Our bodies use messenger RNA to relay the information to our protein factories in our cells to tell our cells how to make proteins,” Morici said.
She said scientists have figured out that they can synthesize this mRNA in the laboratory and plug the genetic information for any virus protein into mRNA. In the case of COVID, that viral protein is known as the spike protein, which is what decorates the surface of the virus and attacks host cells to invade the body.
“The thought is that if we can use the immune response to the spike protein, we can block that virus from invading our host cells,” she said. “We’re basically taking the mRNA, plugging in the instructions for the spike protein so our cells see that mRNA and they are called to make that protein. It gets presented on the surface of the cells so if we are ever infected with the real virus, our immune system will recognize it and mount an immune response. Once the mRNA has done its job, it’s degraded rapidly in the body and doesn’t stay around.”
The Johnson & Johnson and Oxford-AstraZeneca vaccines—which currently are not yet approved for use in the U.S.—are adenovirus vector vaccines. Adenoviruses can cause a variety of illnesses, including the common cold, and scientists are using these viruses to deliver the gene that encodes the information for making the spiked protein to fight COVID-19.
Decoding the data
All this scientific information is great for understanding how the vaccines work, but most people want the dosage and efficacy breakdown to make a decision as to whether the vaccine is right for them. Although the Moderna and Pfizer vaccines are similar, Moderna is a two-dose schedule and the doses are given four weeks apart, while Pfizer’s doses are given three weeks apart. AstraZeneca is also a two-dose vaccine and the doses are given anywhere from three to 12 weeks apart. The Johnson & Johnson vaccine—currently waiting on emergency FDA authorization—is the only vaccine that is a single dose regimen.
In terms of their efficacy, Morici says the Moderna and Pfizer vaccines have excellent track records with 94% to 95% efficacy for preventing mild to moderate COVID-19 and their success rate is even better for severe disease, hospitalization and death. Recent data out of the United Kingdom suggests that waiting 12 weeks for the second dose of the AstraZeneca vaccine increases effectiveness.
“They are saying 76% efficacy after the first dose and 82% efficacy if you wait 12 weeks for the second dose,” Morici said. “Data in the UK shows this vaccine may actually be blocking infection or colonization with the virus, which would then prevent transmission of the virus. We’re seeing a reduction in about 67% of vaccinated individuals and that’s very exciting because if they’re not colonized with the virus in their nasal cavity so they can’t transmit the virus to someone who’s not vaccinated yet. Because the efficacy of this vaccine is lower than the mRNA vaccines, we’re hopeful that the mRNA vaccines are going to be able to reduce infection and transmission as well.”
Morici said the Johnson & Johnson vaccine is reporting an overall efficacy of 66% worldwide, but there was an efficacy rate of 72% in the U.S. Although there are double-digit efficacy percentage differences between the four vaccines, Morici advised individuals to get whichever vaccine is offered to them first rather than waiting to get the vaccine with the highest effectiveness rate. She said these rates are referring to mild to moderate infection, not severe disease.
“Every single one of these vaccines is doing a terrific job of preventing severe disease, hospitalization and death and it’s for this reason I would encourage you to get the first vaccine that is made available to you, no matter what it is, because they are all going to save your life and they will help us get herd immunity.”
Debunking the myths
The misinformation floating around social media has been a major roadblock for many in deciding if they feel comfortable getting the vaccine. Morici outlined some of the most common myths and explained why they are incorrect. The first myth is that mRNA can integrate into a person’s DNA. According to Morici, mRNA is highly unstable and needs ultra-cold storage to protect the vaccine because it breaks down so easily at room temperature.
“Just to get it into the body and our host cells, engineers and scientists figured out that they have to coat it in these lipid nanoparticles, which are miniscule fat bubbles that help protect the mRNA when the vaccine is injected into a recipient. Additionally, mRNA can’t even reach the compartment in our cells where our DNA is housed.”
The same thing for the adenovirus vector vaccines, which are genetically modified so they cannot replicate in the body. Next, Morici said many mistruths have been spread about these vaccines and female infertility. She said there is no scientific evidence that the vaccines affect women’s ability to conceive, and in fact, multiple women in the Pfizer trial actually became pregnant.
One of the most widespread rumors Morici debunks on a regular basis is that the vaccines cause COVID-19.
“They certainly carry the instructions to make a piece of the virus, but there is no way it can cause the disease itself because it is not a live virus,” she explained.
Next, one of the more far-fetched myths is that the vaccines carry microchips to track individuals.
“Microchips are 1,000 times bigger than the tiny lipid nanoparticles, so microchips simply would not fit in vaccines,” Morici said.
Finally, the most feasible misconceptions are that the vaccines were rushed. Morici said on average it takes vaccines about 10 years from the beginning to the end for them to get approved. They take so long because there usually is not a great sense of urgency, they are expensive to develop and for that reason there needs to be proof that they will work before more trials and manufacturing.
“The COVID-19 vaccines were unique because there was an urgent need for them and the platforms were developed over the last 30 years, so researchers already had a tremendous knowledge of them in animals,” Morici said. “The vaccines were designed for the exact purpose of combating a pandemic or an emerging virus. I can promise you, this did not work like magic in a month. Additionally, we already had some phase one data prior to the pandemic because some of the platforms were in use for other diseases, like Zika virus, Ebola virus and HIV/AIDS.”
Morici said although the trials did overlap some of the phases, scientists made sure there was enough supportive data to move on to the next phase.
“All of the participants in these phases are being followed very carefully for safety and efficacy of the vaccines, but instead of waiting for one to finish completely, we started the next phase so we could condense the time.”
Finally, the financial risk was mitigated by the federal government and other agencies that helped offset the risks and the costs. Morici said the government provided more than $26 billion to help finance the vaccines, which was the main reason the vaccines were able to be developed so quickly.
Although some are concerned about side effects, Morici said they are mostly mild to moderate including: headaches, fatigue, pain at the injection site and chills and fever—particularly after the second dose of mRNA vaccines. She said the worst side effect—although treatable—has been allergic reactions from mRNA vaccines, which are typically between two and six cases per 1 million doses that are given. It is thought that the allergic reaction is due to polyethylene glycol that is in the lipid nanoparticles.
“Please remember, it’s so much safer to get the vaccine than to risk getting COVID,” Morici said. “We have thousands of people dying of COVID daily, so your chance of dying with COVID if you’re in a high-risk group is great. Any fear of the unknown with getting a vaccine has to be balanced with the extreme risk and likelihood of disease from this virus. I would really encourage everyone to get vaccinated.”
Lacey Newlin can be reached at 620-227-1871 or [email protected].
