The big question everyone is asking at the moment is how the new variants and strains will affect the efficacy of Covid vaccines
By Dr R. Neerunjun Gopee
Whether we are will be able to stop the spread of the epidemic depends on a) how effectively we apply the social distancing and other public health measures that are recommended, b) the capacity of health systems to treat cases of Covid-19, and c) prevention by means of a vaccine.
The least that can be said is that this pandemic is evolving in ways that have not been seen with earlier ones. If we look back to its more recent predecessor, the AH1N1 pandemic, that was over within a year. There was one big wave that spread all over the world, and it died down with the help of the vaccine that was developed fairly rapidly, and became available and affordable across the world. Because AH1N1 was an influenza virus that caused an influenza-like disease, it became possible to administer the vaccine along with the other two influenza viruses in a triple vaccine that is now given yearly.
AH1N1 viruses circulate among the population as a normal phenomenon, and produce disease when the conditions are conducive – like the influenza virus which attacks during the cold weather, and then we talk about the ‘flu season.’
But, disappointingly, within a few months of its appearance, it became clear that Covid-19 is not a mere influenza or influenza-like, as was assumed it would be because it is a coronavirus like the influenza viruses. Instead, it was affecting all age groups and even children, in whom it produced what was termed a ‘Kawasaki-like’ syndrome (Kawasaki’s disease is an autoimmune inflammation of small arteries), which presented with a severe inflammation of the heart muscle along with red skin patches on the thighs. More than 100,000 children have been affected in the US alone.
Besides, in post-mortem studies, the virus particles were found not only in the lungs but in several other organs as well, for example the kidneys and the nervous system including the brain. In comparison, influenza affects only the upper respiratory passages. That is, it has a certain ‘specificity,’ with respect to the organ system it affects, whereas Covid-19 does not have this specificity since it affects all organs.
The other difference noted is that, unlike the influenza virus, Covid-19 has been mutating, this means that when it multiplies, there are errors in the process so that the new particles of virus are not exactly the same as the original. Mutations are common in nature and affect all living things. But the consequences of mutation are not the same for all organisms, and especially in the case of viruses such mutations may lead to the production of new ‘variants’ which help the virus to spread better and/or to cause more serious disease. That is to become more transmissible to other persons or be more virulent.
When a virus acquires these additional features, it becomes a source of concern., and is aptly called ‘variant of concern or VOC.’ This is the case with the Delta variant, which has followed in the wake of a few other variants, which however, were not spreading as fast as Delta, though they were found in several countries over a short period.
The trouble with the Delta variant is that it is more transmissible more rapidly, and affects more people than the original Covid. The latter affects 2-3 people, designated by the term Reproductive number,’ or R which is therefore 2-3 for it. For Delta, it is 5-6, and takes place in a shorter period.
It is now the fastest spreading variant in several countries, even those that had initially controlled the spread very rapidly and effectively, and has been spreading like wildfire in certain parts of the US, such as Texas where hospitals are overwhelmed.
There is no specific treatment that has been found yet for Covid-19, and that is why scientists, the medical community and health authorities are banking on vaccination as the mainstay of prevention in the long term, because the sanitary measures and rolling lockdowns have been causing much hardship to livelihoods and well-being, as they impact the economic and social activities very negatively.
One positive thing, as was pointed out by Prof Randeep Guleria, Director of the All-India Institute of Medical Sciences New-Delhi, in an interview to the media a few days ago, is that although in certain regions the number of cases is rising, the number of people needing hospitalization or dying has slowed down. Which means that most people are suffering from the milder form of the disease, even if caused by variants.
But the big question everyone is asking at the moment is how the new variants and strains will affect the efficacy of Covid vaccines.
The scientific community is uncovering more information about emerging mutations, variants and strains all the time, and leading vaccine developers are testing and evaluating the efficacy of their vaccines in this light. Some studies have shown that the efficacy of some vaccines extends to the variant as well, but it is too early to make any definitive statement in this regard as yet. More studies over a longer period are required to generate the reliable data on which to base oneself for making firm recommendations.
There is no information forthcoming about whether any case of Delta variant has been detected here, and in any case, we do not have the capacity for genome sequencing that this requires, and this will have to be done in South Africa. However, we are making progress with vaccine coverage, and that is the way forward to control the pandemic. The next step is to vaccinate the younger demographic (13-19) as soon as this is possible, because the Delta variant affects the young as also those with diminished immunity. Meanwhile, let’s continue to ‘stay well, stay safe’.
* Published in print edition on 24 August 2021
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