The Times Herald (Norristown, PA)
Expanding administration
Studies in the U.S. show the Johnson & Johnson vaccine is 72 percent effective in preventing moderate to severe COVID-19 illness and 65 percent effective across all regions, according to Dr. Thomas Ma, chair of the department of medicine at Penn State Health Milton S. Hershey Medical Center.
Though the efficacy rating is less than the PfizerBioNTech and Moderna vaccines, 95 percent and 94 percent respectively, Ma explained that it is still very high.
“The FDA threshold is 50 percent (efficacy),” he said. “I think we were spoiled by the data (for the first two).”
Ma added that the flu vaccine usually reaches at most 60 percent efficacy.
Powell also noted how effective the first two vaccines are and the difficulty for those that follow to reach a similar efficacy rate.
“The first two vaccines that came to the market were amazingly effective,” she said. “It’s going to be hard for any other vaccine to reach that 95 percent efficacy.”
The Johnson & Johnson vaccine was studied in three regions, including South Africa, which has one of the COVID-19 variants, Ma said.
In the three regions, the efficacy ratings, according to Ma, were 72 percent in the U.S., 66 percent in Latin America and 57 percent in South Africa. He also noted the variants that are causing concern were unknown at the time Pfizer-BioNTech and Moderna were going through trials, unlike now with Johnson & Johnson.
“If you look into the details, there’s a more powerful story behind it (the data),” Ma said. “There were zero hospitalizations or deaths in the trials. Even in South Africa there were no patients that were hospitalized.” Ma said the data on all three vaccines is very good.
A different method
The Johnson & Johnson vaccine uses a different mechanism than the Pfizer-BioNTech and Moderna vaccines, making it less fragile when it comes to storage, Ma and Powell noted. This vaccine is stored at a regular refrigeration temperature and has a shelf life of six months.
The Pfizer-BioNTech and Moderna vaccines are messenger RNA, or mRNA, vaccines. The Johnson & Johnson vaccine is viral vector vaccine. Both teach the body’s immune system to fight a spike protein on the coronavirus that causes COVID-19, but they do so in different ways.
The genetic material for the coronavirus spike protein is added to an adenovirus, a virus that causes upper respiratory illnesses such as the common cold, which is then used to get the spike protein genetic material into the body’s cells. The adenovirus is neutralized so the virus cannot divide and cause illness.
“They use a virus that is not infectious to people, kind of like a Trojan horse to get the virus into the body,” Powell said. “It’s just a different way to get the vaccine into you.”
Ma likened the method to using the adenovirus as a cargo ship to deliver the genetic material to the cells.
“This adenovirus gets into the muscle cells, the DNA (genetic material) gets replicated into the muscle cell system and the spike protein is made,” Ma said. “The spike protein is then recognized by our immune system as foreign and generates an immune response. When the real virus comes, which has the spike protein, the immune system recognizes the spike protein, and the immune system will eradicate the virus.”
With vaccine supply continuing to be limited and the available vaccines requiring two doses, Ma and Powell are excited to have a third vaccine in the near future.
“It’s incredibly exciting,” Ma said. “The huge advantage is it just requires one shot so you need fewer doses. Having all three (vaccines) available like that will really help with the concern about vaccine supply.”
Powell agreed and noted the benefits of a vaccine requiring only one shot.
“I think it’s wonderful news,” Powell said. “It makes it so much easier because now it can be one and done versus rescheduling people in three to four weeks and getting them back in, having the infrastructure to do double the work and get the timing right.
“This makes it much more user friendly. You can get it out to more people, once and done, and they’ll be immune, which is really remarkable.”