Distribution: Smooth or full of strife?
In addition to the concern that some people will not take advantage of vaccination against COVID-19, there could be vaccine supply issues down the road, Schaffner said.
Culver agreed. “In the early phases, I expect that there will be some kinks to work out, but because the numbers are relatively small, this should be okay,” he said.
“I think when we start to get into larger-scale vaccination programs — the supply chain, transport, and storage will be a Herculean undertaking,” Culver added. “It will take careful coordination between healthcare providers, distributors, suppliers, and public health officials to pull this off.”
Planning and distribution also should focus beyond US borders. Any issues in vaccine distribution or administration in the United States “will only be multiplied in several other parts of the world,” Culver said. Because COVID-19 is a pandemic, “we need to think about vaccinating globally.”
Investigating adverse events
Adverse events common to vaccinations in general — injection site pain, headaches, and fever — would not be unexpected with the COVID-19 vaccines. However, experts remain concerned that other, unrelated adverse events might be erroneously attributed to vaccination. For example, if a fall, heart attack, or death occurs within days of immunization, some might immediately blame the vaccine product.
“It’s important to remember that any new, highly touted medical therapy like this will receive a lot of scrutiny, so it would be unusual not to hear about something happening to somebody,” Culver said. Vaccine companies and health agencies will be carefully evaluating any reported adverse events to ensure no safety signal was missed in the trials.
“Fortunately, there are systems in place to investigate these events immediately,” Schaffner said.
Pregnancy recommendations pending
One question still looms: Is the COVID-19 vaccination safe for pregnant women? This isn’t just a question for the general public, either, Schaffner said. He estimated that about 70 percent of healthcare workers are women, and data suggests about 300,000 of these healthcare workers are pregnant.
“The CDC’s Advisory Committee on Immunization Practices will speak to that just as soon as the EUA is issued,” he added.
Patients are asking Culver about the priority order for vaccination. He said it’s difficult to provide firm guidance at this point.
People also have “lingering skepticism” about whether vaccine development was done in a prudent way, Culver said. Some people question whether the Pfizer vaccine and others were rushed to market. “So we try to spend time with the patients, reassuring them that all the usual safety evaluations were carefully done,” he said.
Another concern is whether mRNA vaccines can interact with human DNA. “The quick, short, and definitive answer is no,” Schaffner said. The m stands for messenger — the vaccines transmit information. "Once it gets into a cell, the mRNA does not go anywhere near the DNA, and once it transmits its information to the cell appropriately, it gets metabolized, and we excrete all the remnants."
Hewlett pointed out that investigations and surveillance will continue. Because this is an EUA and not full approval, “that essentially means they will still be obligated to collect a lot more data than they would ordinarily,” he said.
How long immunoprotection will last also remains an unknown. “The big question left on the table now is the durability,” Culver said. “Of course, we won’t know the answer to that for quite some time.”
Schaffner and Culver have disclosed no relevant financial relationships. Hewlett was an employee of Pfizer until mid-2019. His previous work as Pfizer’s senior medical director of global medical product evaluation was not associated with development of the COVID-19 vaccine.
This article first appeared on Medscape.com.