According to genome databases, like nextstrain.org, there are now more than 1,000 known variants of the SARS-CoV-2 virus.
Until recently, the ‘variants of concern’ had been named after the places where they were first discovered. But in a move to avoid stigmatising particular countries, the World Health Organisation introduced a new naming system based on the letters of the Greek alphabet. The variants first reported from the UK, South Africa, Brazil and India will now be given the letters ‘alpha’, ‘beta’, ‘gamma’ and ‘delta’, respectively. But the labels will not replace their more complex scientific names.
The new variant discovered in Vietnam appears to be a cross between alpha (B.1.1.7) and delta (B.1.617.2). According to health minister Nguyen Thanh Long, the new strain spreads “quickly by air”, which could explain the rapid rise in the number of new infections in May.
Up to now, Vietnam had escaped relatively lightly, recording some 3,500 confirmed cases and 47 deaths from the beginning of the pandemic to the start of May 2021. The government successfully contained COVID-19 outbreaks by imposing a brief but strict lockdown and comprehensive quarantine restrictions.
But since May, Vietnam has already recorded more than 3,000 new cases – above all in the provinces of Bac Ninh and Bac Giang, where hundreds of thousands of people work in huge production facilities for international technology enterprises.
Determining the course of the pandemic
One might think that those numbers are still relatively low, but the new variants in Asia and elsewhere should be of concern to everyone wherever they live. And that is not just because it means that the pandemic will continue to cause more suffering and deprivation worldwide.
In the medium term, the Northern Hemisphere could also be affected again despite extensive vaccination programs. In a globalised world, such variants spread fast. And if these new strains increasingly adapt to their human hosts, then our antibodies – formed either by vaccination or infection – will no longer protect us at some point. The antigen or PCR tests would no longer detect the variants and instead produce false negatives. And the vaccinations available would also gradually stop working.
That makes it vital to identify variants as quickly as possible using genetic sequencing and to ensure that sufficient amounts of the right types of vaccines are available globally and not just in wealthy nations.
Why is sequencing so important?
Alongside the four apparently most dangerous ‘variants of concern’, there are hybrid strains, such as the one in Vietnam. Some have been around for some time. Yet many of these variants are detected only by chance, as many countries simply do not have the sequencing facilities.
To be able to fight the virus, we have to able to unlock its genetic code, and that is possible only with genomic sequencing. Next generation sequencing (NGS) methods enable scientists to decode the entire viral genome base by base. Researchers are able to detect minuscule changes in the genetic make-up of the virus by looking at fragments of DNA – and thus determine the origin and the spread pattern of variants. And that is the only way of developing appropriate vaccines.
Different strains and the wrong vaccines
There are many indications that virus variants are primarily responsible for the current outbreaks in various parts of Asia. In Sri Lanka and Cambodia, the alpha (B.1.1.7) strain is predominant. From what we know at the moment, the mRNA vaccines produced by BioNtech/Pfizer and Moderna are an effective weapon against that variant. And mRNA vaccines can be adapted relatively swiftly. The AstraZeneca vaccine also offers good protection.
In India and further northwest in Nepal, however, the delta variant (B.1.617.2) has already spread extensively. Nepal has, as a result, seen a steep rise in the number of recorded COVID-19 cases since mid-April. Nepal has been worse hit than India in proportion to its population size.
Genomic sequencing conducted by the Indian National Institute of Virology has identified eight mutations within the spike protein of the delta variant. Two of them have been linked to higher rates of transmission and one of them, as with the gamma variant, has even been associated with immune escape, which enables the pathogens to evade the human immune system.
According to London’s Imperial College, the delta variant is 20% to 80% more transmissible than the alpha variant. In addition, the virus may be able to evade immunity conferred by previous infections or vaccination. British studies indicate that existing BioNtech/Pfizer and AstraZeneca vaccines may not be as effective when it comes to protecting us from this variant.
The variant discovered in Vietnam is a hybrid of the alpha and delta variants. Only 1 million of the 96-million-strong population have been vaccinated – with AstraZeneca, which protects well against the alpha variant but, as mentioned above, is probably not as effective against the delta variant. In the second half of the year, Vietnam hopes to receive additional mRNA vaccines from Biontech/Pfizer and Moderna. So far, however, it has not been investigated how any existing vaccines cope with the variant discovered in Vietnam.
In Bangladesh, by contrast, the beta variant (B.1.351) has sparked a rapid rise in cases. AstraZeneca has been reported as offering “minimal” protection against this strain. This is a big problem, as the main vaccine available in Bangladesh is Covishield, the name for AstraZeneca manufactured in India.
Unfair global distribution of vaccines
While many industrialised nations aim to have vaccinated the majority of their adult population by late summer, many poorer Asian, African or Latin American countries have not even been able to launch their vaccination campaigns.
According to a recent study in the medical journal The Lancet, the world’s richest countries have secured some 70% of supplies of the five top COVID-19 vaccines despite having less than 16% of the globe’s population. According to the WHO, only 0.2% of the population in poorer countries have been vaccinated against SARS-COV2. The Economist estimates that mass vaccinations will not start there until 2024 at the earliest, if programs continue at this pace.
The initiative COVAX, co-organised by the WHO, is meant to work toward more equitable access to COVID-19 vaccines. But from the outset, richer countries have signed simultaneous bilateral contracts with several vaccine manufacturers and – apart from a few generous donations – swept the market clean.
“The pandemic is far from over,” WHO Director General Tedros Adhanom Ghebreyesus has warned. He has vehemently criticised the huge inequality in the distribution of vaccines between poor and rich countries.
But if the coronavirus variants continue to spread as rapidly as they are and to adapt to their human hosts, that inequality could come home to roost for wealthier nations.