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New variants of COVID-19 may prolong the duration of the virus

11 August 2021 | Story André Damons | Photo Anja Aucamp

Prof Burt read more — Prof Felicity Burt from the University of the Free State (UFS) and the National Health Laboratory Services (NHLS) holds an NRF-DST South African Research Chair in Vector-borne and Zoonotic Pathogens Research. She is also an expert on arbovirology in the UFS Division of Virology.

New variants of severe acute respiratory coronavirus 2 (SARS-CoV-2) have the potential to influence the size and duration of waves of infection and may prolong the duration of COVID-19’s stay with us. Despite the development of vaccines and the technology available to adapt vaccines in the future to address the emergence of new variants, it is extremely unlikely that COVID-19 will ever be eradicated.

The emergence of new variants has illustrated the importance of continually monitoring circulating variants for changes in viral proteins associated with cell binding (in other words, influencing entry of the virus into a cell) and immune responses (which would influence vaccine efficacy and reinfections).

Prof Felicity Burt from the University of the Free State (UFS) and the National Health Laboratory Services (NHLS), who holds an NRF-DST South African Research Chair in Vector-borne and Zoonotic Pathogens Research, says the current vaccines are effective against severe disease, but do not prevent transmission. Hence, complete eradication of the virus is unlikely, as the virus will continue to circulate at low levels in the population even if high levels of vaccine coverage are achieved. Prof Burt is also an expert on arbovirology in the UFS Division of Virology.

“To date, the only pathogen that has been eradicated globally is the smallpox virus. This was achievable because of a highly efficacious vaccine and because smallpox caused a disease that was readily recognisable, enabling rapid isolation of afflicted patients. In contrast, a virus such as SARS-CoV-2 that can cause asymptomatic infections in which the person is unknowingly infected and able to shed and transmit the virus, is probably impossible to eradicate,” explains Prof Burt.

Development of affordable treatment options remains important

The current vaccines are, however, able to reduce the severity of the disease until a vaccine is available that prevents complete transmission of SARS-CoV-2; therefore, the development of affordable treatment options remains important. Novel therapeutics, such as an antiviral drug that interrupts replication of the virus, or monoclonal antibodies that neutralise the virus, would go a long way to contribute to the treatment of infections.

“Currently, monoclonal antibody therapy is available in higher-income countries. Monoclonal antibodies mimic our natural antibody response, targeting specific regions of the virus, neutralising the virus, and stopping it from entering cells. Monoclonal antibodies have been used to treat other viral infections such as Ebola; however, they have significant limitations due to cost, availability, and high specificity, meaning that mutations in emerging variants could influence their efficacy. They are unlikely to be an affordable option in lower-income countries.”

Mutations become problematic

According to Prof Burt, viruses have a propensity to acquire mutations, or changes, in their genetic make-up during replication, and as expected, this virus has changed during the pandemic and will inevitably continue to mutate.

“These mutations become problematic if they influence the way the virus is transmitted between people, or if the disease profile changes and the virus causes a more severe disease, or if the changes result in a virus that is not recognised by the body's immune response. In other words, the virus is capable of hiding from, or can escape, the immune response that a person has developed as a result of a previous natural infection or from vaccination.

“If the virus has changed such that an existing immune response does not recognise it, then a person can become reinfected. Hence, changes in the ability to escape immunity are considered to confer an advantage to the virus. Although there are changes in all regions of the viral genes, we are concerned with changes that occur in the gene that codes for the spike protein. This protein is responsible for binding and entry of the virus into cells, hence changes in the spike protein that allow the virus to more readily enter cells are considered to be an advantage to the virus.”

Variants of interest vs variants of concern

Prof Burt says there is now some evidence suggesting that antibodies produced in response to the Beta variant – the dominant variant during the second wave in South Africa – are less efficient at neutralising the Delta variant of the virus. In addition, there is evidence suggesting that the Delta virus can replicate to higher levels in the body, resulting in a higher viral load. Although the kinetics of each variant are still not completely understood, the combinations of higher viral load, and the potential for reinfections to occur will likely contribute towards a larger wave of infection.

“The World Health Organisation (WHO) and international partners characterise emerging variants as variants of concern (VOC) or variants of interest (VOI). Although there are multiple new variants globally, only a small proportion of these meet the definition. The Lambda variant, initially recognised in South America, is deemed a VOI. This is a level below VOC, indicating that it has mutations that are known or have the potential to affect the characteristics of the virus and that the prevalence is increasing in multiple countries over time. Currently, Lambda is not a concern in SA. In contrast, a VOC has the same characteristics as a VOI, but in addition, has one or more of the following: increased transmissibility or is associated with change in disease severity or clinical presentation, or the public health and social measures are less effective against the variant,” says Prof Burt.

Vaccines will likely need to be adapted to accommodate future variants

It is impossible to predict which variants may emerge next, explains Prof Burt. “Fortunately, although the current vaccines may not prevent mild disease, they have all been shown to reduce the incidence of severe disease and fatalities. The technology for adapting vaccines is available – but of course – if a vaccine has to be adapted, it will take some time for that to be available. As this virus is now well established globally and will continue to evolve over the years, it is likely that, in the future, vaccines will be required to be adapted to accommodate circulating variants.”

“Although there is some reduction in vaccine efficacy against the currently circulating variants, there are fortunately high levels of protection against severe disease and hospitalisation in people who have received the single-dose Johnson & Johnson vaccine or both doses of the Pfizer vaccine. In other words, they are fully vaccinated,” says Prof Burt.

Despite reduced effectiveness and potential for vaccine breakthrough, it is still important for people to be vaccinated, as it reduces viral load and duration of virus shedding. Less viral replication means that the virus has less chance to mutate, with less chance of new variants emerging.

News Archive

Conference: Expanded ARV treatment

2005-03-02

VENUE: University of the Free State, Bloemfontein, South Africa
DATE: 30 March 2005 - 1 April 2005

ARV Programme as on 24Feb Download Word document
Programme Special events Download Word document

Official web site www.fshealth.gov.za/subsites/arvc

Rationale for the Conference
At the time of the planned Conference, much ground would have been covered, both in the Free State and in South Africa, in respect of the expanded public sector ARV treatment programme in respect of research, experiences in practice, training of staff, treatment of patients, lessons learned, successes and failures, etc. The time would then be quite opportune to share these in a systematic manner with other provinces and countries, as well as with the large variety of stakeholders and role players in the ARV and related domains, be they academics and researchers, policy makers and service/facility managers, the variety of caregivers, and the community organisations and affected patients.

The Conference and current research
The proposed Conference is, firstly, directly linked to the current research on the public sector roll-out of ARV treatment in the Free State conducted by several research institutions (e.g. CIET, CHSR&D, UCT Lung Institute). Secondly, the Conference could and would serve as a forum for other research groups in the country and further a field to report and share knowledge and experiences on ARV treatment and related initiatives. Lastly, the Conference will stage a golden opportunity for researchers and scientists, on the one hand, and policy makers, managers, and caregivers (as knowledge users), on the other hand, to engage in cross-disciplinary discourse on this mutual and topical theme.

Theme of Conference
Expanded ARV treatment in the Free State: sharing experiences

Focus
The focus is primarily on public sector ARV treatment in the Free State, but also initiatives/activities/perspectives of relevance to the Free State elsewhere in the country at large and further a field, as well as relevant ARV initiatives in the public, private, NGO and FBO sectors. Bear in mind, however, that ARV treatment is but part of a much more comprehensive approach to HIV and AIDS. The Conference will, therefore, not narrowly focus on the ARV treatment programme only. The broader context, other relevant dimensions, and a comprehensive approach to the challenges of HIV, AIDS and TB are of equal importance.

The purpose of the Conference
Enhance meaningful exchange, mutual understanding and collaboration among researchers, scientists, policy makers, managers and practitioners in the field of ARV treatment and related fields.

Share experiences in the various spheres of ARV treatment and related spheres (policy, management, practice, research, training, public-private-civil society sectors).

Record, reflect and report on the establishment of the ARV treatment programme in the Free State, and in within the context of the comprehensive HIV/AIDS programme.

Disseminate important research results on ARV treatment and related themes to health policy makers, managers, practitioners, communities and to the research community.

Stimulate discourse among various disciplines and various stakeholders/role players involved in ARV treatment and related programmes.

Sensitise and acquaint researchers to the requirements of policy makers, managers and practitioners in respect of ARV treatment and related fields.

Facilitate the implementation of research results in ARV treatment policy, programmes and practice.

Dissemination of Conference-related information
Information generated during the Conference could feed into policy, management and practice of ARV treatment, the training accompanying such programme, and the existing body of knowledge. After the Conference the information will be disseminated via the Internet and by scientific and popular publications.

Date and duration
Set for 30 & 31 March & 1 April 2005; to commence at 09:00 on the first day (30 March) and to end at 16:30 (1 April) the third day.

Format and scope of Conference
Alternating plenary, parallel sessions and debates focused on topical issues and interest groups. The Conference will strive to be maximally interactive and participative.

Themes and topics to cover:

Policy, management and health services/practice (various levels and contexts – clinical treatment, information, IT systems, pharmacy, laboratories, nutrition)
Research covering all relevant disciplines and diverse dimensions of ARV treatment and related themes
Training and evaluation of training
Patients, communities and civil society organisations
Public, private, NGO, FBO initiatives and partnerships

Emphasis will be on the Free State, however, with of significant involvement from other provinces, SADC countries, and countries further a field. The thrust will be to export lessons and experiences from the Free State, but also to import lessons and experiences from other provinces, countries and sectors.

Presenters
Key presenters from the Free State, other provinces, South Africa, from the private, FBO and NGO sectors, and from several other countries

Delegates
About half of the delegates will be Free State stakeholders and role players (all levels and all contexts). The other half will be role players and stakeholders in the ARV and related fields from other provinces, the national level, and other countries, as well as from the private, public and non-governmental sectors.

Focused workshops
Provision will be made for half-a-day or one-day workshop initiatives on the third day (1 April 2005).

Enquiries
For more information please contact:

Prof Dingie van Rensburg
Centre for Health Systems Research & Development
University of the Free State
PO Box 339
Bloenfontein
SOUTH AFRICA
9300

Contact:
Carin van Vuuren
Conference Organiser
Centre for Health Systems Research & Development
University of the Free State
P.O.Box 339
Bloemfontein
South Africa
9300
Tel +27 (0) 51 401 2181
Fax +27 (0) 51 4480370
Cell 0832932890
e-mail: arvconference.hum@mail.uovs.ac.za

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