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The new Omicron variant: What we know and don’t know

01 December 2021 | Story André Damons | Photo Charl Devenish

Prof Burt read more — Prof Felicity Burt, expert in arbovirology in the Division of Virology at the University of the Free State (UFS) and the National Health Laboratory Service (NHLS).

Even though not much is yet known about the new COVID-19 variant, Omicron, the presence of a high number of mutations – more than 30 – in the spike protein of the variant raises concern.

This is according to Prof Felicity Burt, expert in arbovirology in the Division of Virology at the University of the Free State (UFS) and the National Health Laboratory Service (NHLS). According to her, although Omicron is highly transmissible, further epidemiological data is required to determine if it is more transmissible than the Delta variant.

On Friday 26 November, the World Health Organisation (WHO) declared the new variant, B.1.1.529, a variant of concern (VOC) and assigned it the name Omicron. This assignation was based on advice from the Technical Advisory Group on SARS-CoV-2 Virus Evolution (TAG-VE), an independent group of experts responsible for monitoring and evaluating emerging variants. The following are considered when categorising a newly identified variant – are there mutations (changes in the viral genes) that are known, or that have the potential, to affect the characteristics of the virus, such as transmissibility, disease severity, immune escape, diagnostic or therapeutic escape; is there significant community transmission or increasing prevalence in multiple countries over time; are the public health and social measures effective against the variant.

With each new variant, the public health concerns are dependent on the transmissibility of the variant, the ability of the virus to escape immunity from natural infection or from vaccination, and the severity of illness caused by the variant or any change in clinical presentation. In addition, the ability of current diagnostic assays to adequately detect the variant and effectiveness of public health and social measures, must be considered.

We know, we don’t know

Answers are derived from existing epidemiological data, laboratory research, and theoretical considerations. Although we can make some predictions based on the mutations identified and the location of these mutations, the epidemiological data and laboratory research are essential to answer with certainty, and this can take some time. The presence of a high number of mutations – more than 30 – in the spike protein of Omicron, raises concern. What do we know and what don’t we know?

“What we don’t know is whether these mutations have changed the severity of disease caused by the virus. We do know that the diagnostic PCR tests currently used in South Africa are not compromised by the presence of these mutations, and in fact, one of the molecular assays commonly used to target three regions of the virus, can be used as a rapid biomarker to detect the variant. Although sequencing of the genome is used as confirmation, this assay provides a useful rapid biomarker that can be used to detect the presence of the variant; subsequently, PCR results have shown that the variant is likely already present in most provinces in the country,” says Prof Burt, who currently holds an NRF-DST South African Research Chair in vector-borne and zoonotic pathogens research.

There is also preliminary epidemiological evidence that reinfections are occurring. According to her, the occurrence of reinfections suggests some degree of immune escape; however, we do not know the extent of immune escape or the contribution of waning immunity towards reinfections. “Laboratory tests, in which the live virus is tested against samples from both recovered and vaccinated people, are required to confirm whether existing antibodies can neutralise the variant. The tests for neutralising antibodies require specialised facilities and is dependent on culturing the virus.

“These tests are already underway in the country and should provide more information in the coming weeks.

Neutralising antibody tests, although time consuming, are relatively easy to perform compared to tests to determine the role played by other arms of the immune response.”

Vaccines still best option to fight COVID-19

Prof Burt, who has worked on viral haemorrhagic fevers and arboviruses at the National Institute for Communicable Diseases (NICD), says it is known that vaccines are highly effective in reducing the severity of disease and fatalities in individuals infected with other variants, such as Beta and Delta, despite mutations in critical regions of the spike gene in the variants.

The epidemiological data acquired from cases and the results of laboratory tests for neutralising capability will contribute towards understanding the effectiveness of the vaccine against Omicron. The questions regarding severity of the disease and level of protection from previous infection and vaccines are priority areas to understand the impact of this variant. The early identification of the variant and the initiation of vital research and data analysis highlight the importance of genomic surveillance.

Cases of Omicron have already been confirmed in Israel, the United Kingdom, Europe, Australia, and Africa. Travel restrictions have previously been shown to be ineffective in stopping the geographical spread of new variants, merely delaying the inevitable, and at significant cost to economies. “We know with certainty that vaccination has reduced the severity of illness and death with previous variants; even in the face of reduced neutralising ability, there was sufficient protection to save lives,” says Prof Burt.

She concluded, “Globally, the impact of vaccination is evident in countries experiencing fourth waves, with a reduced number of deaths compared to previous waves. Many decisions in life are based on a risk assessment and consideration of the pros and cons. Vaccines save lives. Vaccines definitely boost waning immune responses from natural infection.”

“This is certainly not the time to reject the vaccine based on perceived risks from inaccurate social media spreading harmful disinformation compared to the known risks associated with contracting COVID-19 and the known protection against severe disease afforded by the vaccines.”

News Archive

Fight against Ebola virus requires more research

2014-10-22

Dr Abdon Atangana
Photo: Ifa Tshishonge

Dr Abdon Atangana, a postdoctoral researcher in the Institute for Groundwater Studies at the University of the Free State (UFS), wrote an article related to the Ebola virus: Modelling the Ebola haemorrhagic fever with the beta-derivative: Deathly infection disease in West African countries.

“The filoviruses belong to a virus family named filoviridae. This virus can cause unembellished haemorrhagic fever in humans and nonhuman monkeys. In literature, only two members of this virus family have been mentioned, namely the Marburg virus and the Ebola virus. However, so far only five species of the Ebola virus have been identified, including: Ivory Coast, Sudan, Zaire, Reston and Bundibugyo.

“Among these families, the Ebola virus is the only member of the Zaire Ebola virus species and also the most dangerous, being responsible for the largest number of outbreaks.

“Ebola is an unusual, but fatal virus that causes bleeding inside and outside the body. As the virus spreads through the body, it damages the immune system and organs. Ultimately, it causes the blood-clotting levels in cells to drop. This leads to severe, uncontrollable bleeding.

Since all physical problems can be modelled via mathematical equation, Dr Atangana aimed in his research (the paper was published in BioMed Research International with impact factor 2.701) to analyse the spread of this deadly disease using mathematical equations. We shall propose a model underpinning the spread of this disease in a given Sub-Saharan African country,” he said.

The mathematical equations are used to predict the future behaviour of the disease, especially the spread of the disease among the targeted population. These mathematical equations are called differential equation and are only using the concept of rate of change over time.

However, there is several definitions for derivative, and the choice of the derivative used for such a model is very important, because the more accurate the model, the better results will be obtained. The classical derivative describes the change of rate, but it is an approximation of the real velocity of the object under study. The beta derivative is the modification of the classical derivative that takes into account the time scale and also has a new parameter that can be considered as the fractional order.

“I have used the beta derivative to model the spread of the fatal disease called Ebola, which has killed many people in the West African countries, including Nigeria, Sierra Leone, Guinea and Liberia, since December 2013,” he said.

The constructed mathematical equations were called Atangana’s Beta Ebola System of Equations (ABESE). “We did the investigation of the stable endemic points and presented the Eigen-Values using the Jacobian method. The homotopy decomposition method was used to solve the resulted system of equations. The convergence of the method was presented and some numerical simulations were done for different values of beta.

“The simulations showed that our model is more realistic for all betas less than 0.5. The model revealed that, if there were no recovery precaution for a given population in a West African country, the entire population of that country would all die in a very short period of time, even if the total number of the infected population is very small. In simple terms, the prediction revealed a fast spread of the virus among the targeted population. These results can be used to educate and inform people about the rapid spread of the deadly disease,” he said.

The spread of Ebola among people only occurs through direct contact with the blood or body fluids of a person after symptoms have developed. Body fluid that may contain the Ebola virus includes saliva, mucus, vomit, faeces, sweat, tears, breast milk, urine and semen. Entry points include the nose, mouth, eyes, open wounds, cuts and abrasions. Note should be taken that contact with objects contaminated by the virus, particularly needles and syringes, may also transmit the infection.

“Based on the predictions in this paper, we are calling on more research regarding this disease; in particular, we are calling on researchers to pay attention to finding an efficient cure or more effective prevention, to reduce the risk of contamination,” Dr Atangana said.

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