The “emergency use” designation from the U.S. Food and Drug Administration will mean that the treatments are still considered “experimental” and will require informed consent from recipients. However, preliminary data from human trials found both vaccines to be more than 90% effective — far above the levels many experts had predicted.
Impending early use of these vaccines, however, is unlikely to spare the U.S. a harsh winter in the grips of the pandemic, according to experts. Confirmed COVID cases and deaths have been surging in most parts of the country, including Wisconsin, which recorded 7,090 new cases and 92 deaths on Tuesday.
“We’re anticipating emergency use authorization will be given within the next few weeks,” said Andrew D. Badley, who leads the COVID-19 task force at Mayo Clinic in Rochester, Minnesota.
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“As the vaccine is rolled out and people begin to receive it, the beneficial effects will be restricted. It is unlikely to impact the epidemiology of the disease on a state, national or global level until a majority of people have received the vaccine.”
Badley said vaccinating the majority of people “will definitely take many months to a year or more.”
In Wisconsin, health leaders have been preparing for a vaccine campaign that “will be the most extraordinary public health undertaking” in the state’s history, according to Department of Health Services Deputy Secretary Julie Willems Van Dijk.
The first to receive the new vaccine will be health care workers and people in nursing homes and long-term care facilities. Stephanie Schauer, Wisconsin’s immunization program manager, estimated there could be several hundred thousand people in this first group.
“The number will greatly outweigh the number of doses we receive in the beginning,” Schauer said. Recipients will need to receive two doses of vaccine either 21 days or 28 days apart.
“No matter where you live in Wisconsin, you will have access to the vaccine,” Willems Van Dijk said, stressing that supplies will reach rural areas. She said national distribution of the vaccine will cost an estimated $5.5 billion to $6 billion.
The launch of the vaccination program will not replace efforts already underway to stop the spread of the virus. Health authorities will need to continue testing for COVID-19 and Americans will still need to adhere to a strict regimen of mask-wearing, social distancing and avoiding crowds and indoor gatherings.
In the U.S., “vaccination of select high-risk individuals may start by the end of the year, but most likely the majority of vaccines will be released during the first quarter of 2021,” said Amy Hartman, assistant professor in the Center for Vaccine Research at the University of Pittsburgh.
“The major hurdles will be scaling up production and then distributing the vaccine, first to high-risk individuals and then to the general public.”
The vaccines developed by other companies, including AstraZeneca and Johnson & Johnson, use a similar strategy to those developed by Pfizer and Moderna. All target a protein on the virus called Spike, which allows the virus to dock onto human cells and infect them.
James Conway, medical director of the UW Health Immunization Program, praised the preliminary data from the Pfizer and Moderna vaccines, which use a new kind of technology, intended to be safer and more effective. He said federal officials are just waiting for vaccine recipients to pass the two-month mark.
“With unexpected side effects, generally if they’re going to show up, they’re going to show up within the first couple of months,” Conway said.
Vaccines work by tricking our immune system into thinking it is responding to a virus when it is only responding to part of that virus.
The Moderna and Pfizer vaccines employ something called messenger RNA, which carries genetic code. Instead of using a larger portion of the virus, these vaccines use only the portion of code needed for the virus’ critical Spike protein.
“There has been this gradual march toward safer and more effective vaccines,” Conway said. “This is the most advanced version.”
If the other vaccines now in clinical trials go on to receive approval, it will speed up the process of inoculating the majority of Americans.
Vaccinations are vital to achieving what is called “herd immunity.” Herd immunity is when so many people have gained immunity — whether through vaccination or prior illness — that a virus struggles to find new hosts to infect.
Uncertainties remain about the vaccines closest to approval.
Badley cautioned that the preliminary results from Pfizer and Moderna indicate their vaccines greatly reduce the number of people who become sick from COVID-19. However, scientists are not yet certain that the vaccines prevent people from becoming infected and simply not showing symptoms.
“We need to be very diligent about determining that,” Badley said.
One of the most challenging aspects of the new coronavirus has been its ability to infect people who do not go on to show any symptoms. These people feel healthy and have no idea they are infected and can pass the virus to others.
Another crucial question that has yet to be answered is how long protection from any of the potential vaccines will last.
“We don’t have enough people who have been vaccinated for a long period of time,” Badley said.
Also preliminary results released by Pfizer and Moderna have only involved small numbers of vaccine recipients and have yet to appear in peer-reviewed journals.
Still, “the results are very exciting so far,” said William R. Hartman, a University of Wisconsin-Madison School of Public Health assistant professor of anesthesiology. Hartman is leading the UW portion of the recently restarted Phase 3 trial of AstraZeneca’s potential COVID vaccine.
Conway said the high effectiveness rates of the vaccines and the fact that some 16 million to 24 million health care workers will receive it first should convince skeptics.
“We wouldn’t do this if we didn’t believe it was safe and worthwhile,” he said.
At the University of Pittsburgh, Hartman said vaccine makers still need to gather results from larger groups of recipients who have been studied for longer periods.
“That’s important,” she said, “because some very rare side effects may not become apparent until either a large number of people receive the candidate vaccine, or until enough time passes.”
Wisconsin officials said health care workers should be able to get vaccinated where they work. Workers will also be dispatched to vaccinate nursing home residents where they live.
Residents will be able to get vaccinated by their primary doctors or at drive-through and community health care facilities.