Johnson & Johnson has begun human trials of its coronavirus vaccine after its experimental vaccine protected monkeys from getting infected. When all the six monkeys were vaccinated, they were protected from lung disease, and furthermore five out of six monkeys were protected from the virus as there was traces of the virus found in their nasal swab. Until the human trials are completed this monkey data offers the best clue about whether the vaccine will work or not.
The US government has backed Johnson & Johnson (J&J) by giving them 456 million dollars as funding to speed the production of the vaccine to end the pandemic. J&J recently started a clinical trial of its vaccine in the United States and Europe to test the vaccine in humans. More than 30 human trials for coronavirus vaccines are underway around the world. But these trials will take several months to complete.
The other vaccines in development might require two doses of the vaccine to work however the J&J’s coronavirus vaccine provided protection to the monkeys with only one dose, according to the study. A virologist at Columbia University Angela Rasmussen believes that this week has been a very good one as there are two vaccines that work on monkeys. But according to her, it will be too early to perform trials on humans at large scales, as no shortcuts can be taken.
This study came days after a similar study was published about the vaccine being developed by Moderna in collaboration with the National Institute of Health. The two of them however work in different ways. The vaccine being developed by Moderna sends a type of genetic material called messenger RNA into cells. The cells use this vaccine RNA to produce spike protein which is found on the surface of coronavirus, this then produces an immune response from the body. Some RNA vaccines are being tested for other diseases but none of them have been licensed for use in humans yet.
In the study of the Moderna vaccine, the researchers gave the monkeys two shots of the vaccine over a period of four weeks. After a month of the vaccination, the researchers infected the monkeys with the coronavirus. In some of the monkeys, the virus could not be detected while in others there was a replication of the virus which slowly disappeared. Pfizer as well as Moderna has begun their phase 3 trials of their respective mRNA vaccines.
In contrast, the J&J coronavirus vaccine uses a virus called Ad26 which after modification by the researchers carries the spike protein gene from the coronavirus. The Ad26 virus can enter into the human cells but once inside it cannot replicate them. The host cells of Ad26 then use the spike gene to produce coronavirus proteins.
J&J’s chief scientific officer Dr. Paul Stoffels said that what gives the researchers confidence is that they can test the vaccine by a single shot and learn whether it will protect humans or not. He said that previous tests of this type of vaccine in other viruses showed that a second dose increased the protection significantly. But during a pandemic, a single shot vaccine gives a significant advantage as there are a lot of issues with second doses involving making people come back for their second dose.
J&J plans to test in its phase one trial, which started this week, that whether one dose of the vaccine is enough or two doses are required. They also plan to start phase three trials at large scale in the second half of September.