There are factors contributing to HIVDR; one could be inherent mutation of the virus others mostly reported are sub-optimal adherence of patients on ART and target of the drug.This could be due to selective drug pressure and adaptation. To address this issue, there has to be standardized treatment program in the country...

Dear Yimam,

 As a student or teacher,

Go to  read more HIV treatment adherence or compliance literature on scientific web free (PubMed) or googleScholar and even Wikipedia. Also, there is ample rationale and evidence both pharmacological, toxicological and medical and public health on why it is an issue.

I wish you all the best.

Dear Dr Yimam Getaneh,

You have asked a very interesting question. To understand the relation between ART scale up and drug resistance, we need to understand that HIV drug resistance (DR) is of 2 types. Acquired and Transmitted DR.

Acquired DR occurs when resistance mutations emerge because of drug-selective pressure in individuals receiving antiretroviral therapy.

Transmitted DR occurs when previously uninfected individuals are infected with a drug-resistant virus.

Now, as a country starts scaling up its ART, two factors will directly impact adherence. The larger the number of patients on ART, the greater the absolute number of people who will have issues of poor drug adherence. Also, multiple factors are likely to impact drug supply chain logistics adding to poor drug adherence. It is well known that a 70-80% adherence is more dangerous in helping acquired resistance as it presents the perfect millieu where the sensitive strains are suppressed but resistance strains replicate and thrive. Thus acquired resistance will increase in the population.

 The transmtted resistance too will get affected. To understand this, we need to understand the concept of Viral fitness. Viral fitness is defined as the overall capacity of a virus to infect, replicate and produce mature infectious progeny in a defined host environment. HIV is a quasispecies. What this means is that in any given individual, multiple genetic variants of HIV exist simultaneously. The wild virus strains have a greater viral fitness and are more predominant than the resistant variant. They are also far more likely to be transmitted and survive in the new host.

Lets say there is a country that has a million people infected with HIV and that has no access to ART . The wild strain will predominate here among the HIV infected population. Now this country introduces ART and scales it up rapidly. Lets say that it reaches 70% coverage in a few years. Now, these 0.7 million people will have a significant percentage among them who have issues of poor adherence and have developed drug resistance. The sexual partners who acquire the infection from this subgroup will start with a drug resistance strain. Over time the transmitted drug resistance will increase. 

Of course, as the scaling up improves further and issues of adherence are tackled suitably, the transmission rates will decline. You can make a mathematical model for this but I hope it is clear that scaling up of ART in a country will have a direct impact on both acquired and transmitted drug resistance.

Hope this helps

regards

See these links may be useful for you.

1) Drug Resistance | HIV/AIDS Fact Sheets | Education ...

 https://aidsinfo.nih.gov/education.../drug-resistance

 Traduire cette page29 avr. 2015 - A person can initially be infected with drug-resistant HIV or develop ... to help you address any issues before you start taking HIV medicines.

 2) Drug Resistance - AIDS.gov

 https://www.aids.gov/hiv...hiv.../drug-resistance/

 Traduire cette page1 juin 2012 - HIV Drug Resistance Basics. When you are first diagnosed with HIV infection, your blood is full of copies of the HIV virus, all looking for CD4 ...

Best Regards.

Nouhoum

3) HIV Drug Resistance Database

 hivdb.stanford.edu/

 Traduire cette pageA curated database containing nearly all published HIV RT and protease sequences: a resource designed for researchers studying evolutionary and ...HIVdb Program - ‎Drug Summaries - ‎Genotype-Rx - ‎CPR

Resistance is predestined and there’s little that can be done to effectively detect minority variants and to prevent them from causing a rebound in viral load. Tremendous progress has been made in terms of developing drugs with high antiviral activity that are also easier to take than their less potent predecessors. By developing drug combinations that have high barriers to resistance, that are less toxic, and are easier to take, we are potentially talking about regimens that won’t inevitably lead to resistance. Attempting to combat resistance, once it has already occurred, is most difficult, given the presence of minority variants that may have a selective advantage upon changing a regimen. The key is to develop regimens that limit the growth of these variants, which means developing regimens that are capable of suppressing virus for a very long period of time. If we can start patients on regimens that are very strong and have durable effects, and are easy for the patient to adhere to, we’ll be one step ahead.

Charpentier C, Dwyer DE, Lecossier D, et al. Co-evolution and competition of viral populations with distinct resistance genotypes in patients failing treatment with protease inhibitors [Abstract 48]. Antiviral Therapy 7(suppl 1):S55, 2002.

https://www.nature.com/articles/d41586-019-02316-x