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11 December 2019 | Story Leonie Bolleurs
Aids read more

According to Global Statistics, there were approximately 37,9 million people across the globe with HIV/Aids in 2018. They also state that in 2018, an estimated 1,7 million individuals worldwide became newly infected with HIV. 

In the city of Masvingo, Zimbabwe, Claris Shoko is a Statistics lecturer at the Great Zimbabwe University. In her PhD thesis at the University of the Free State (UFS) in the Department of Mathematical Statistics and Actuarial Sciences, she presented the argument that the inclusion of both the CD4 cell count and the viral-load counts in the monitoring and management of HIV+ patients on antiretroviral therapy (ART), is helping in reducing mortality rates, leading to improved life expectancy for HIV/Aids patients. 

She received her doctoral degree at the December UFS Graduation Ceremonies, with her thesis: Continuous-time Markov modelling of the effects of treatment regimens on HIV/Aids immunology and virology. 

CD4 cell count and viral-load count

Dr Shoko explains: “When the human immunodeficiency virus (HIV) enters the human body, the virus attacks the CD4 cells in their blood. This process damages CD4 cells, causing the number of white blood cells in the body to drop, making it difficult to fight infections.”

“Clinical markers such as CD4 cell count and viral-load count (number of HIV particles in a ml of blood) provide information about the progression of HIV/Aids in infected individuals. These markers fully define the immunology and the virology of HIV-infected individuals, thereby giving us a clear picture of how HIV/Aids evolve within an individual.”

Dr Shoko continues: “The development of highly active antiretroviral therapy (HAART) has helped substantially to reduce the death rate from HIV. HAART reduces viral load-count levels, blocking replication of HIV particles in the blood, resulting in an increase of CD4 cell counts and the life expectancy of individuals infected with HIV. This has made CD4 cell counts and viral-load counts the fundamental laboratory markers that are regularly used for patient management, in addition to predicting HIV/Aids disease progression or treatment outcomes.”

In the treatment of HIV/Aids, medical practitioners prescribe combination therapy to attack the virus at different stages of its life cycle, and medication to treat the opportunistic infections that may occur. “The introduction of combined antiretroviral therapy (cART) has led to the dramatic reduction in morbidity and mortality at both individual level and population level,” states Dr Shoko.

Once HIV-positive patients are put on cART, the effectiveness of treatment is monitored after the first three months and a further follow-up is done every six months thereafter. During the monitoring stages, CD4 cell count and viral load is measured. Patients are also screened for any tuberculosis (TB) co-infection and checked for any signs of drug resistance. These variables determine whether or not there is a need for treatment change. 

She continues: “Previous studies on HIV modelling could not include both CD4 cell count and viral load in one model, because of the collinearity between the two variables. In this study, the principal component approach for the treatment of collinearity between variables is used. Both variables were then included in one model, resulting in a better prediction of mortality than when only one of the variables is used.”

“Viral-load monitoring helps in checking for any possibilities of virologic failure or viral rebound, which increases the rate of mortality if not managed properly. CD4 cell count then comes in to monitor the potential development of opportunistic infections such as TB. TB is extremely fatal, but once detected and treated, the survival of HIV/Aids patients is assured,” Dr Shoko explains.

Markov model

She applied the Markov model in her study. The model, named after the Russian mathematician Andrey Markov, represents a general category of stochastic processes, characterised by six basic attributes: states, stages, actions, rewards, transitions, and constraints. 

According to Dr Shoko, Markov models assume that a patient is always in one of a finite number of discrete states, called Markov states. All events are modelled as transitions from one state to another. Each state is assigned a utility, and the contribution of this utility to the overall prognosis depends on the length of time spent in each state. For example, for a patient who is HIV positive, these states could be HIV+ (CD4 cell count above 200 cells/mm3), Aids (CD4 cell count below 200 cells/mm3) and Dead.

“Markov models are ideal for use in HIV/Aids studies, because they estimate the rate of transition between multiple-disease states while allowing for the possible reversibility of some states,” says Dr Shoko, quoting Hubbard and Zhou.

“Relatively fewer HIV modelling studies include a detailed description of the dynamics of HIV viral load count during stages of HIV disease progression. This could be due to the unavailability of data on viral load, particularly from low- and middle-income countries that have historically relied on monitoring CD4 cell counts for patients on ART because of higher costs of viral load-count testing,” Dr Shoko concludes

News Archive

Position statement: Recent reporting in newspapers
2014-10-03

 

You may have read reports in two Afrikaans newspapers, regarding recent events at the University of the Free State (UFS). Sadly, those reports are inaccurate, one-sided, exaggerated and based not on facts, but on rumour, gossip and unusually personal attacks on members of the university management.

Anyone who spends 10 minutes on our Bloemfontein Campus would wonder what the so-called ‘crisis’ is about.

We are left with no choice other than to consider legal action, as well as the intervention of the South African Press Ombudsman, among other steps, to protect the good name of the institution and the reputation of its staff. No journalist has the right to launch personal and damaging attacks on a university and its personnel, whatever his or her motives, without being fair and factual. In this respect, the newspapers have a case to answer.

But here are the facts in relation to the reports:

  1. No staff member, whether junior or senior, is ever suspended without hard evidence in hand. Such actions are rare, and when done, are preceded by careful reviews of our Human Resource Policies, labour legislation and both internal and external legal advice. Then, and only then, is a suspension affected. A suspension, moreover, does not mean you are guilty and is a precautionary action to allow for the disciplinary investigation and process to be conducted, especially where there is a serious case to answer.
  2. At no stage was the Registrar instructed to leave the university; this is patently false and yet reported as fact. We specifically responded to the media that the Registrar does outstanding work for the university and that it is our intention for him to remain as our Registrar through the end of his contract in 2016.
  3. The Rector does not make decisions by himself. Senior persons, from the position of Dean, upwards, are appointed by statutory and other senior committees of the university and finally approved by Council. No rector can override the decision of a senior committee, and this has not happened at the UFS even in cases where the Rector serves as Chair of that committee. The impression of heavy-handed management at the top insults all our committee structures, including the Institutional Forum – the widest and most inclusive of stakeholder bodies at a university – which reports directly to Council on fairness and compliance of selection processes.
  4. In the case of senior appointments, Council makes the final decision. Council fully supports the actions taken on senior appointments, including a recent senior suspension. The fact that one Council member resigns just before the end of his term, whatever the real reason for this action, does not deter from the fact that the full Council in its last sitting approved the major staffing decisions brought before it. The image therefore that the two newspapers try to create of great turmoil and distress at the university, is completely unfounded.

Even if we wanted to, the university obviously cannot provide details about staffing decisions, especially disciplinary actions in process, since the rights of individuals should be protected in terms of the Human Resource Policies and procedures of the UFS. But that does not give any newspaper the right to speculate or state as fact that which is based on rumour or gossip, or to slander senior personnel of the university. For these reasons, we have been forced to seek legal remedy and correction as a matter of urgency.

Make no mistake, underlying much of the criticism of the university has been a distress about transformation at the UFS; in particular, the perception is created that white colleagues are losing their jobs. The evidence points in the opposite direction. Our progress with equity has been slow and we lag far behind most of the former white universities; that is a fact. More than 90% of our professors are white; most of our senior appointments at professorial level and as heads of department are still overwhelmingly white. Reasonable South Africans would agree that our transformation still has a long way to go and only the mean-spirited would contend otherwise. But based on the two Afrikaans newspaper reports, an impression is left of the aggressive rooting out of white colleagues.

In the past few years the academic standard of the university has significantly improved. We now have the highest academic pass rates in years, in part because we raised the academic standards for admission four years ago. We now have the highest rate of research publications, and among the highest national publication rate of scholarly books, in the history of the UFS. We have one of the most stable financial situations of any university in South Africa, with a strong balance sheet and growing financial reserves way beyond what we had before. We now attract top professors from around the country and other parts of the world, and we have the highest number of rated researchers, through the National Research Foundation, than ever before. And after the constant turmoil of a number of years ago, we now have one of the most stable campuses in South Africa. Those are the facts.

The UFS is also regarded around the world as a university that has become a model of transformation and reconciliation in the student body. The elections of our Student Representative Council are only the most visible example of how far we have come in our leadership diversity. Not a week goes by in which other universities, nationally and abroad, do not come to Kovsies to consult with us on how they can learn from us and deepen their own transformations, especially among students.

Rather than focus on what more than one senior journalist, in reference to the article in Rapport of 21 September 2014, rightly called ‘a hatchet job’ on persons and the university, here are the objective findings of a recent survey of UFS stakeholders: 92% endorse our values; 77% agree with our transformation; 78% believe we are inclusive; and 78% applaud our overall reputation index.  Those are very different numbers from a few years ago when the institution was in crisis.

This is our commitment to all our stakeholders: we will continue our model of inclusive transformation which provides opportunities for study and for employment for all South Africans, including international students and colleagues. We remain committed to our parallel-medium instruction in which Afrikaans remains a language of instruction; we are in fact the only medical school in the country that offers dual education and training in both Afrikaans and English for our students - not only English. We provide bursaries and overseas study opportunities to all our students, irrespective of race. And our ‘future professors’ programme is richly diverse as we seek the academic stars of the future.

We are not perfect as a university management or community. Where we make mistakes, we acknowledge them and try to do better the next time round. But we remain steadfast in our goal of making the UFS a top world university in its academic ambitions and its human commitments.

END

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