COVID-19 vaccine effectiveness ‘better than we anticipated’
Two COVID-19 vaccines that are expected to be submitted soon for federal review and licensure are showing “very promising data,” members of the Iowa Board of Regents heard Wednesday.
Pat Winokur, executive dean of the University of Iowa Carver College, is the principal investigator for the Pfizer vaccine trial conducted at the school. She told Regents members she wanted to dispel any public misconceptions that researchers are dangerously expediting the release of a COVID-19 vaccine.
“We are not really skimping on safety,” Winokur said. “We have huge numbers of people who are being studied.”
Pfizer and Moderna have completed human trials of their vaccines and tested their effectiveness on 44,000 people and 30,000 people, respectively.
Pfizer just finished its required two-month waiting period to examine any serious side effects of the vaccine and are expected to go to the U.S. Food and Drug Administration within days for review.
Once approved, manufacturing may start.
Previous research of other coronavirus strains helped inform the development of the current COVID-19 vaccines, Winokur said. COVID-19 is similar to two other coronaviruses in modern history: SARS, which appeared in China in 2002 and MERS, which appeared in the Middle East in 2012.
During its phase three trial, Pfizer distributed the vaccine to 44,000 people and gave 50 percent of them a placebo. Results from the trial showed that out of the 170 people who tested positive for COVID-19, only eight were from the vaccine group.
For the 10 people who suffered severe COVID-19 infection, nine were from the placebo group and one was from the vaccine group, Winokur said.
Both Pfizer and Moderna’s vaccines have a 95 percent effective rate, which is better than the 60 percent to 70 percent professionals initially expected.
That rate is similar to the effectiveness of the measles vaccine.
In contrast, flu vaccines are about 75 percent effective in young, healthy adults, Winokur said.
“Lots of very promising data,” Winokur said. “Better than we anticipated.”
Symptoms and side effects
The Pfizer vaccine, which comes in two doses, can lead to fever, fatigue and chills. Respondents said the second dose resulted in more side effects than the first, Winokur said, but side effects were more prevalent in adults ages 18 to 64 years old, than those 65 and older.
Winokur said she witnessed the side effects first hand and said people were still able to work, mostly reporting only 24 hours of fatigue.
“They responded very nicely to Tylenol or ibuprofen. It was not anything that’s concerning,” Winokur said. “It’s a good sign it’s a tolerated vaccine.”
When will it be released and who will get it first?
This year, about 20 to 30 million doses of the Pfizer vaccine will be produced and will most likely be distributed to health care workers and first responders, Winokur said. Because recipients need to take two doses, about 12.5 million people will initially receive them as early as mid-December, she said.
Once more doses of the vaccine is produced, Winokur said she expects them to be offered to long-term care facilities, people with significant medical conditions and other essential workers.
By April or May of 2021, vaccines will be available to young adults and children.
“We are going to have a scarce resource for quite a number of months,” Winokur said. “They can’t make enough vaccines.”
But Moderna, which is waiting to finish its two-month waiting period, is not far behind in the process. Other companies are going through clinical trials as well, Winokur said.
Now, researchers will have to study the longevity of the vaccine, the safety of repeat dosing and examine its effect on children and pregnant women.
“That will really help us to flatten the curve much faster,” Winokur said.