While the most ideal solution to the current COVID-19 pandemic may be developing a vaccine, a UC Berkeley study found that current laboratory measurements for vaccine success may lead to consequences.
According to the study, the first vaccine will likely be approved based on a strong antibody response in phase 2 clinical trials. However, Marc Hellerstein, campus professor in the department of nutritional sciences and toxicology and study author, has major concerns with using an antibody response as the sole measure of protective immunity.
“Antibodies really are not enough. In fact, there’s a lot of data that says the more antibodies you have, the sicker you get,” said Hellerstein. “We need a different perspective and use different criteria for evaluating when a vaccine should be approved.”
By reviewing previous literature on coronaviruses, including severe acute respiratory syndrome and Middle East respiratory syndrome, Hellerstein found that antibodies are not the major type of protective immunity from coronaviruses.
Hellerstein added that this is because anti-coronavirus antibodies sometimes only partially bind to coronaviruses instead of neutralizing them, which can actually help the viruses enter our cells.
“For most viruses, antibodies are great, but for coronaviruses, there’s a lot of evidence that antibodies are not sensitive for mild infections,” Hellerstein said. “They last, at most, a couple years, sometimes even a few months, and they may even cause damage.”
Instead, Hellerstein suggested T-cells can be more sensitive, long-lasting and more related to protective immunity than antibodies. Hellerstein cited the yellow fever vaccine as a popular example of this, which showed that T-cells have a powerful signature in response to effective vaccines.
According to Hellerstein, one reason why T-cells are not commonly used as a marker of immunity is because measuring T-cells specific to a virus is relatively harder than measuring antibodies.
“I’m very concerned that there’s a lot of pressure to make something that may or may not be completely validated,” Hellerstein said. “We need to have very good laboratory markers to give us confidence that good things are going to happen.”
The consequence of developing an ineffective vaccine could be a “disaster,” as it could not only progress the pandemic, but also decrease people’s faith in vaccines, Hellerstein added.
In the worst-case scenario, the effectiveness of antibodies may wear off after 6 months. Alternatively, some people might not be able to make enough antibodies, causing them to get more sick than they would have without the vaccine, he added.
“I want us to get as good a vaccine as possible,” Hellerstein said. “Research in the next six months should focus not just on antibodies but T-cells, and we need to support that research to really figure this out before we make a mistake.”