An American team has discovered how the hepatitis virus enters the liver: in some respects it resembles the approach used by the SARS-CoV-2 coronavirus. Now a vaccine is possible.
The pandemic, and the ensuing race against time to find drugs and vaccines against COVID-19 which has attracted massive investments and research, has rebooted the virology sector which, until 2020, had become something of a niche.
Alongside studies into coronavirus, research into other viruses is also being conducted more frequently and in greater depth, particularly viruses that still pose unresolved problems. Of these, one of the most widespread and damaging is without doubt the Hepatitis C virus (the abbreviation of which is HCV). Whilst effective drugs have been available for some years now, a vaccination has yet to be invented. Yet the available drugs are costly and not without side-effects.
Covid-19 and Hepatitis C: two “similar” viruses
The absence of a vaccine can be explained by the questions still surrounding the biology of this virus, and the problems involved in cultivating it in the lab, a fact which has long hampered in-depth experiments. But now the situation could well change, as virologists from the National Institute of Allergy and Infectious Diseases (NIAID) in the US have, for the very first time, described how the virus enters the host cell in detail, providing a potential target for new vaccine strategies and treatments.
As illustrated in Nature science magazine, the Hepatitis C virus behaves in much the same way as SARS-CoV-2 (the virus responsible for the COVID-19 illness). This is because it uses a protein on its surface, called E2 (comparable with the coronavirus spike), to latch onto another found on the surface of human cells, called CD81 (resembling the ACE2 receptor which intervenes in the case of the coronavirus).
Once the fusion is made (an event fostered by an acidic cellular environment), E2 changes its spatial conformation, thereby enabling the virus to enter the host cell.
If it were possible to create specific monoclonal antibodies against the E2 protein typical of this virus, as indeed proved the case with the spike, or to teach the body to identify it and develop specific antibodies to counter it, as was the case with COVID-19 vaccines, in all likelihood the Hepatitis C virus would merely pose a relative threat, and a mass vaccine could potentially be rolled out.
An illness which is hard to identify
It is estimated that Hepatitis C affects 70 million people worldwide. It leads to fibrosis, cirrhosis and the need for a transplant for at least half of all those who catch it. It is transmitted through blood (for example, by using infected syringes), but for many years it remains asymptomatic and continues to damage the liver. At the same time, it spreads from one person to another through the host, who is unaware of the illness but contagious nonetheless. When the virus manifests itself, it is often too late and the liver is compromised. For this reason, the search for a vaccine has been considered a priority for some time now.