NEWS of a new variant has been circulating recently in international epidemiological circles implying the world is about to enter another year – its fourth – of living with COVID-19.
The coronavirus has so far defied prediction and medical experts differ in their outlook and what might lie ahead for the world in the year 2023.
Meanwhile, following the confirmation of the new and rapid-spreading variant – named ‘omicron’, in neighbouring South Africa, Zimbabwe is once again on high alert for COVID-19.
The wildly transmissible omicron variant currently circulating globally has already claimed more than 250 000 people in the US alone and infected more than a million people per day at its peak.
But it is not yet clear whether omicron is more easily spread from person to person compared to other variants, or whether infection with it causes more severe disease.
Following COVID-19 and its many variants, the World Health Organisation (WHO) has given B.1.1.529 the name omicron and classified it, like its preceding variants beta and delta, as a variant of concern. However B.1.1.529 has a genetic profile very different from other circulating variants of interest or concern. According to medical experts, it does not appear to be a ‘daughter of delta’ or ‘grandson of beta’ but rather represents a new lineage of SARS-CoV-2.
Some of its genetic changes are known from other variants known to affect transmissibility or allow immune evasion, but many are new and have not been studied yet.
While some predictions can be made, experts are still studying how far the mutations will influence its behaviour.
Although some of these changes (variants), have no impact on how the virus behaves, others may affect some of its properties such as how easily it is transmitted or its ability to overcome our immune defences
These variants are labelled a ‘variant of interest’ or ‘variant of concern’ by WHO.
A ‘variant of interest’ possesses genetic markers that are predicted to affect its transmission, how well diagnostics, treatments or vaccines work, or if they appear to be responsible for an increased proportion of cases.
A ‘variant of concern’ meets these criteria, but also shows evidence of being more contagious, causing more severe disease, or being less susceptible to public health measures, vaccines, diagnostic tests and or therapeutics.
Since the coronavirus, COVID-19 first emerged in late 2019, in Wuhan, China, its genetic material has undergone numerous changes, some of which have altered how easily it is transmitted and the severity of disease it caused.
Although some of the variants of concern identified so far appear able to partially evade the immunity generated by vaccination, evidence confirms COVID-19 vaccines help to reduce the spread of COVID-19 and are highly effective at reducing hospitalisation and deaths associated with the disease.
Currently, China is battling the new COVID-Omicron XBB variant.
Although WHO has no data yet on the seriousness of XBB.1.5 and no indication that it makes people’s health more compromised than previous variants, but WHO is concerned at how quickly the XBB.1.5 spreads, noting that it is the most transmissible sub-variant ever detected.
Virologists and public health experts are diligently analysing the transmissibility, disease severity and ability of the virus to ‘escape’ the immune response in vaccinated or recovered people.
Medical studies are being conducted to find out whether the new lineage virus shows changes in its transmissibility, its ability to infect vaccinated or previously infected individuals, and so on.
Additionally, epidemiological laboratory studies are examining the properties of this virus and its viral growth characteristics are compared with those of other virus variants to determine how well the virus can be neutralised by antibodies found in the blood of vaccinated or recovered individuals.
The full significance of the genetic changes observed in B.1.1.529 will become apparent only when the results from all the different studies are assessed.
This is achieved through whole genome sequencing of samples that have tested positive for the virus.
The process entails checking every sequence obtained for differences compared to what is known circulating in South Africa and the world.
When multiple differences are observed, a red flag is immediately raised and further research is carried out to confirm what was found.
Tracking variant requires a concerted effort.
It is a complex, demanding and expensive undertaking; but indispensable.
It permits medical experts to understand the virus better and to devise the best strategies to combat them and the new lineage of SARS-CoV-2.
South Africa and the UK were the first countries to implement nationwide genomics surveillance for SARS-CoV-2.
The Network for Genomics Surveillance in South Africa has been monitoring changes in SARS-CoV-2 since early April 2020.
This was a valuable tool to understand better how the virus spread.
Late in 2020, it detected a new virus lineage – 501Y.V2, which later became known as the ‘beta’ variant.
The beta variant spread much more efficiently between people compared to the ‘wild type’ or ‘ancestral’ SARS-CoV-2 and caused South Africa’s second pandemic wave, and was classified as a variant of concern by the WHO.
Previously during 2021, another variant of concern called delta spread over much of the world including South Africa, causing a third pandemic wave.
The new SARS-CoV-2 variant named named B.1.1.529 was identified by the Network for Genomics Surveillance member laboratories during routine sequencing in South Africa with small numbers also reported in neighbouring Botswana.
The World Health Organisation has given B.1.1.529 the name omicron and like beta and delta, has classified it as a variant of concern.
If B.1.1.529 spreads further it will take a while before its effects, in terms of disease severity, can be assessed.
Though there is yet no evidence for any clinical differences it is known that cases of B.1.1.529 infection have increased rapidly in Gauteng, South Africa where the country is experiencing its fourth pandemic wave.
This suggests easy transmissibility, albeit on a background of much relaxed non-pharmaceutical interventions and low number of cases.
Scientists cannot tell as yet whether B.1.1.529 is transmitted more efficiently than the previously prevailing variant of concern, delta or whether infection with it causes more severe disease.
In Zimbabwe four waves of COVID-19 were experienced since the outbreak of the pandemic, with the peak recorded during the second wave during the festive period between November 2020 and February 2021.
In the first week of January 2023, Zimbabwe recorded 29 COVID cases but no cases of the new Omicron XBB variant were recorded.
Nonetheless, the Ministry of Health and Child Care in Zimbabwe, continues to encourage people to get vaccinated against the virus.
Everybody must be vaccinated.
The goal of vaccine is not to prevent cases, because that is not possible.
The goal is to keep people out of the hospitals, out of intensive care and out of the morgues.
Dr Tony Monda BSc, DVM, is currently conducting Veterinary epidemiology, and Agro-economic research in Zimbabwe. For views and comments, email: tonym.MONDA@gmail.com