The acute phase of hepatitis C (HCV) is often a confusing term, because it has nothing to do with the amount of symptoms someone experiences or whether the disease has had an effect on a person’s body. Acute hepatitis C occurs during the first 6 months of an infection, regardless of signs of infection or disease severity.
The Window Period
After someone contracts hepatitis C, the body’s immune system begins to react to the virus by producing antibodies to the infection. Different immune systems will take different amounts of time to create antibodies, but on average, hepatitis C antibodies become detectable in a person’s body anywhere from 3 to 12 weeks after a person has contracted HCV. The time period between initial infection and detection is called the window period. For those who suspect they may have been recently infected with HCV, it’s important to wait to be tested until the window period has subsided – otherwise, it’s possible to receive a false negative result. Once an antibody test indicates a positive result, a follow-up PCR test is administered.
PCR tests (polymerase chain reaction) look for a short sequence of the hepatitis C virus’ DNA (called RNA), rather than the antibodies that are produced to fight the infection. PCR tests are more sensitive and can detect HCV sooner than antibody tests, but they are not usually administered first, because they cost significantly more than antibody tests. If someone knows they’ve recently been exposed to HCV, a PCR test will be able to provide a more accurate result sooner, and the quicker someone is diagnosed and begins treatment, the more likely they are to clear the infection.
Once someone is diagnosed with hepatitis C, the next step is to perform blood tests measuring levels of certain proteins and enzymes in the liver to determine if the liver is still functioning properly. These tests are called liver functioning tests (LFTs). When HCV damages cells in the liver, enzymes leak into the bloodstream and certain enzyme levels increase. On average, it takes around 7 to 8 weeks after initial infection before the virus effects the liver. This period is called the incubation period.
During the acute phase of infection, someone will test positive for the virus or antibodies to the virus after there is a detectable level in the body (the window period), and individuals will test positive for elevated enzymes after the virus has begun effecting the liver (the incubation period). However, some folks in the acute phase will test positive for the infection, but their LFTs will remain healthy.
Acute Phase Symptoms
Upwards of 65% of people do not experience any noticeable signs or symptoms during the acute phase of infection. For those who do experience symptoms, they are typically generalized and can include such things as: mild fatigue, loss of appetite, nausea, or low-grade fever. Of the 25-35% of people who notice symptoms, only 20% of those develop jaundice (yellowing of the skin and eyes). When jaundice occurs, it is an indicator that the liver’s functioning has been compromised by the hepatitis C virus.
Even when individuals experience signs or symptoms related to HCV, they often are unaware they are infected, because they do not seek medical attention or their symptoms are similar to other short term infections, and HCV isn’t always suspected.
Anywhere between 15-30% of people who contract HCV clear the virus on their own during the acute phase of infection. Strong immune systems will eliminate viral particles and infected cells circulating throughout the system, and the virus will no longer be detectable. Once the body has cleared the infection, the virus will no longer appear on a PCR test, but antibodies indicating that the individual had an HCV infection will remain for several years or longer. Unfortunately, those antibodies do not protect against further HCV infections.
Factors Contributing to Clearing HCV
While some common factors seem to exist across those who clear HCV during the acute phase, it’s not yet clear to researchers all of the reasons why one person is able to clear the infection on their own and another is not. Things that increase the likelihood of someone clearing the infection include:
The age someone contracts HCV – the younger, the more likely they’ll clear the infection
Sex – women have a higher likelihood of clearing HCV
Noticeable signs and symptoms – people who have more symptoms during the acute phase have a higher chance of clearing the infection
Immune system response – the healthier the immune system and T-cell response, the more likely they’ll clear HCV
Genotype – those with genotype 3, for instance, have a higher chance of clearing the virus than those with genotype 1
Transfusion – those who contracted HCV through blood transfusion have a higher viral load and are at greater risk of progressing to chronic hepatitis C
When does acute hepatitis C become chronic hepatitis C?
After someone has had the hepatitis C virus for over 6 months, they are considered to be in the chronic stage of HCV. This occurs in 70-85% of those who contract HCV. A diagnosis of chronic hepatitis C means that the hepatitis C virus was still detectable after 6 months and on at least two occasions. When someone has been diagnosed with chronic hepatitis C, it’s highly unlikely that the person will clear the virus on their own.