Covid19: variants on the loose….Dr Rana Jawad Asghar

China has been reported to have a major surge of Covid19 infections. Western media is reporting hundreds of thousands of new infections and thousands of daily deaths. This has happened after Chinas reversal on its Zero Covid policy. Under the policy, which saw millions of people quarantined after an infection was found, China used its immense and strict state power to implement these restrictions and that resulted with very few deaths in China while the world paid a heavy price by millions of deaths. China gained that critical time to vaccinate its huge population and once it felt comfortable it opened itself up and scrapped the restrictions.

However, SARS-COV-2 (the virus which causes Covid19) was not staying idle. It first produced multiple variants to evolve and be a better fit. An evolutionary trait of survival of the fittest and in Covid19 we saw many new variants coming and each one was more infectious (easier to pass on infection from one to another) than the previous ones. According to some researchers, the Delta variant not only was more transmissible than all previous variants but also increased hospitalisation rates and deaths. Then Omicron came on the scene which was once again more transmissible than all previous variants. But then we started seeing sub-variants of Omicron and each one was a bit more infectious than the previous one. Not only more transmissible but also more immunity evading. That means you could still be infected even if you have been vaccinated or acquired natural immunity through a prior infection. However, hospitalisation and death rates are much lower in those who have been vaccinated and boosted as compared to the unvaccinated.

Chinas recent surge is reported to be due to an Omicron subvariant BF7. However even in China genomic sequencing (genetic testing which tells about their ancestry, like DNA testing but much more in depth and scope) is very limited. BF7 variant had its round of the world around last fall but as China had strict restrictions then so their population was still vulnerable to this immune evading variant. However, in the rest of the world the variant scene was changing fast. Before December 2022, XBB sub-variant of Omicron was the dominant strain but in the last four weeks another sub-variant XBB 1.5 is now replacing XBB at a very fast pace in the US. It seems to be most infectious till date and the world is focusing on it because of its speed with which it has moved from 4% to nearly 50% in around four weeks. Its also reported to be the most immunity evasive and has the ability to infect even some of those who have been vaccinated with recent bivalent vaccine. However, disease is reported to be milder in the vaccinated group.

In Pakistan, government officials accepted the presence of XBB but denied the presence of BF7. That probably could be true as the world, excluding China, has moved ahead and now the predominant strain is XBB which is more transmissible than BF7. But in Pakistan, genomic sequencing is negligible and with very little Covid19 testing happening now we are pretty much living in the dark. An organised and well-designed testing and genomic surveillance is the only way to be abreast of ongoing situations to have effective disease control strategies. There is no guarantee that there will not be another variant like Delta which increased hospitalisations across the world.

So, what should we do to stay protected? I think the most effective and most ignored intervention is to improve the ventilation of buildings. From the start of this pandemic, we knew that by just opening a window and door we could reduce disease chances to eighteen times. Secondly, get vaccinated and boosted. You could still be infected but with lower chances of severe disease. Third, wear a good quality mask (not surgical) if you are in an indoor setting with poor ventilation. There is no herd immunity against Cholera so why do you expect it against a virus which is fast churning its immunity evading offshoots?

Courtesy The Express Tribune