A new study from the University of Arizona Health Sciences reports that SARS-CoV-2, the virus that can cause the respiratory disease COVID-19, gives those infected with it a pain-relieving effect, which ultimately makes it easier for the virus to spread between people. According to the researchers, this pain-relieving effect may explain why so many people are asymptomatic in the early days of the illness, an issue that is driving the spread of the virus.
At this point in the pandemic, researchers understand how the virus infects its human host: by leveraging the ACE2 receptor on cell membranes to enter the infected person’s body. More recently, another study has identified a second receptor that may also be used by the SARS-CoV-2 virus to infect people, one called neuropilin-1.
The neuropilin receptor plays a big role in experiencing pain specifically when a protein called VEGF-A binds to it. The new study points out that SARS-CoV-2 binds to the neuropilin receptor in the same way as VEGF-A, reversing the pain signaling triggered by the latter protein. It only took “extremely low doses” of the SARS-CoV-2 spike protein to reverse the pain signaling caused by VEGF-A binding to the neuropilin receptors.
This pain relief may explain why many people who contract SARS-CoV-2 are able to go up to several days without symptoms, or only with mild symptoms, all the while shedding the virus to everyone around them. Additional research on this is needed, however, to determine what kind of role the pain relief plays in the overall course of the virus.
As well, the researchers note that this finding has paved the way for a potential future class of non-opioid painkillers, something desperately needed in light of the addiction potential of these drugs. The study’s corresponding author Dr. Rajesh Khanna explained:
We are moving forward with designing small molecules against neuropilin, particularly natural compounds, that could be important for pain relief. We have a pandemic, and we have an opioid epidemic. They’re colliding. Our findings have massive implications for both. SARS-CoV-2 is teaching us about viral spread, but COVID-19 has us also looking at neuropilin as a new non-opioid method to fight the opioid epidemic.