A vaccine regimen intended to prevent chronic HCV infection was tested in a double-blind placebo-controlled trial. It failed. The incidence of chronic HCV infection was the same in the vaccinated group as in the placebo group.
Hepatitis C is a virus that has infected millions of people worldwide. In 75-85% of cases, the infection becomes chronic and can lead to death from liver cancer or cirrhosis. There is a vaccine for hepatitis B that is given to most babies at birth, but there is no vaccine for hepatitis C. Hepatitis C is more common than B, and most chronically infected people don’t know they have it. If they know they have it, effective treatment is available but is very expensive. Studies have shown that people with hepatitis C who inject drugs rarely seek treatment. It would be great if high-risk people could be offered a vaccine to prevent chronic infection.
In January 2021, The New England Journal of Medicine published the results of a large (548 subjects) randomized, double blind, placebo controlled trial of a vaccine regimen designed to prevent chronic HCV infection in high-risk people who had recently injected drugs. It did not cause serious adverse effects. It was effective for producing antibodies and for lowering the peak HCV RNA level, but it failed to prevent chronic HCV infection. The rate of chronic infection was the same in the vaccine group as in the placebo group.
This negative vaccine trial serves as a reminder of just how remarkable the experience with Covid-19 vaccines has been. We now have several effective vaccines that are already available in the US or likely to be approved soon, and both China and Russia have developed their own effective vaccines. One might be fooled into thinking any vaccine based on valid scientific principles is likely to be effective, but this study shows that even when a vaccine “ought” to work, it may not. That’s why carefully controlled studies are always necessary.
Conclusion: There is still no vaccine to prevent chronic hepatitis C
This study got negative results, but there is good reason to hope future studies may come up with an effective way to prevent the chronic infections with HCV that lead to deaths or the need for liver transplants. Fingers crossed.
This article was originally published in the Science-Based Medicine Blog.