More than 3.9 million Johnson & Johnson (J&J) vaccines are being distributed across the United States, two days after the Food and Drug Administration (FDA) gave emergency use authorization.
J&J has said it will distribute the vaccine to states and local governments based on the size of the local adult population, as well as distribution from federal vaccination centers and selected pharmacies to perform the vaccination.
Unlike the Moderna and Pfizer vaccines, Johnson & Johnson’s vaccine requires only one dose to achieve full immunization. Another advantage is that J&J’s vaccine can be refrigerated at 2-8°C (36-46°F), which significantly reduces its distribution costs.
During testing, it was shown to be 85% effective in preventing severe disease and 100% effective in preventing hospitalizations and deaths after 28 inoculations for people who were given the vaccine.
The vaccine was also tested in regions where potentially more dangerous variants of the coronavirus have emerged, such as Brazil and South Africa. The data collected show that it is effective in preventing all variants of the virus known to date.
How does it work?
Johnson & Johnson’s vaccine also differs from its counterparts in that it does not use messenger RNA (mRNA) technology, which teaches the cell to make proteins to develop an immune response.
J&J uses a viral vector approach, which involves introducing coronavirus genetic material for the immune system to identify through the gene of a virus already known to the human body, adenovirus 26.
Adenoviruses are common viruses in the human environment and are normally responsible for colds and flus. The researchers used a modified adenovirus that can enter the cell but cannot replicate the disease.
Once dosed, the adenovirus attaches to the surface layer of the cells, where it is absorbed into the cell and travels to the nucleus to release its DNA. The adenovirus is modified not to replicate, however, the coronavirus protein gene can be read and replicated into a molecule, mRNA.
Like DNA, ribonucleic acid (RNA) functions as the genetic code strand that transmits information essential for the functioning of our systems, such as protein synthesis (a process in which our cells create proteins essential for our bodies to survive).
The mRNA leaves the nucleus and the cell’s molecules read the sequence to begin producing the coronavirus’ protein peaks, which will be shredded into fragments by the cells and brought to the cell’s surface.
The now-familiar adenovirus sets off alarms in the immune system alerting it that a new organism is attacking causing the system to identify the coronavirus protein in time and develop an immune response for future infections.
Johnson & Johnson’s adenovirus follows decades of research on other pathogens. In July 2020 the first adenovirus sequence-based vaccine to prevent Ebola was approved for general use. Johnson & Johnson is also testing to counter other viruses such as HIV and Zika.
As of Sunday, the United States has administered more than 75.2 million doses. Also, 24.8 million Americans, (about 7.5% of the population), have already received the two doses of the mRNA vaccines. By the end of June J&J expects to have 100 million doses ready for distribution, Pfizer and Moderna have guaranteed that they will have enough stock to immunize 300 million people by the summer.