How fast does the medicament work in reducing the viral load?


Is it possible to predict how fast the viral load decreases after starting medication? Is it reasonable to expect reduction of the number of viruses after one week of the treatment? If yes, how by how many? Or it depends?

I take Viread (Tenofvir disoproxil fumarate 245 mg). Do different medicines have different efficacy and speed? Also, what’s the difference between 245 mg and 300 mg? Do the latter work better/faster?

1 Like

Hi @arb,

This paper provides a lot of information about your questions:

HBV DNA reduction happens over months rather than weeks. It depends on what level you start with, but the paper seems to say that you should expect around 10,000-fold reduction after 3 months of therapy. After 10 months, you have ~90% chance of undetectable HBV DNA if you are HBeAg-negative and ~70% if you are HBeAg-positive.

Yes, TDF is one of the most effective antivirals for HBV and is used as a first-line treatment. Older drugs, such as lamivudine and adefovir, are less effective at reducing HBV DNA and keeping it down.

My understanding is that there is the same amount of active ingredient in both of these doses. They are just calculating the weight based on either just the amount of active ingredient, or the active ingredient plus other ions associated with it.

Hope this helps,


Hello @Arb and @ThomasTu I was just reading what you were saying and if it can help I wanted to share my experience with antivirals therapy. and I think it really depends on the individual response to the virus.
I’m 58 y.o. always healthy until I was diagnosed June/July 2023 with Acute HBV with symptoms that lasted for few months.
( muscle pain weight and muscle loss etc) HBV DNA in the millions
on October 27 2023 my hepatologist suggested I’d start TDF due to the fact that my AST and Alt were high with high HBV DNA .
October 27 2023 started TDF therapy HBV DNA 170.000.000
December 19 2023 HBV DNA 55.000 and HBVeag positive
February 2 2024 HBV DNA 2070. HBeAg positive
May 3 2024 HBV DNA 30. HBeAg positive ALT and AST almost normal.
as you can see in 5 months of TDF my viral load has gone from 170.000.000 to 30
just wanted to share my antivirals journey .
best Gregory


Hi @Gregory , it is interesting about your acute HBV journey. How about HBV profile during your treatment monitoring (HBsAg, Anti HBs ,AntiHBc IgM , AntiHBc ) . Most acute HBV infections in adults are spontaneous clearance approximately 95% within 6months after symptoms appear .I hope that you will be fine and completely recovery.

Hi yes unfortunately there hasn’t been any seroconversion within the 6 months, I’m still positive (HBsag. )
I guess e I’ m in that 5% that turns Chronic. but I’m still hoping about seroconversion even though more times goes by slimmer chances I think.

You didn’t touched at all Hbsag quantitative.
Hbv dna in most of the cases will be undetected after taking medication for one year or less.

Hbsag quantitative is the most important to my understanding, it show’s the level of liver inflammation.

In my case hbsag quantitative has ben as follow:

I have been asking to have an Hbsag quantitative many times but my hepatologist says it’s irrelevant.

You also didn’t mention if you have done liver elastography which measures the stiffness of the liver.

On my case in the beginning was 5.17 kpa and now after two years on treatment is 4.95 kpa

Hi I have done ultrasounds several times I have not done fibroscan yet I’m doing it next month.
Did you also have Acute HBV and didn’t clear it?

I have chronic hepatitis B.

It was my mistake because I didn’t read your post properly as you have acute not chronic as I thought.

Hopefully you will clear it

@Gregory @ThomasTu thank you!

1 Like

In my case, The HBV DNA was undetected after taking Enticavor for three months

1 Like