Is Delta Plus more virulent? Can a recovered patient get reinfected? 5 big questions answered
The world is grappling with the more virulent strain of the coronavirus, the Delta Plus variant. It has been spreading rapidly, causing more infections. Some reports even claim that it is impervious to vaccines and therapies generally used to treat Covid-19 patients.
But is that a reality? How dangerous is the delta plus variant? And how long with the coronavirus disease continue to wreak havoc. Dr Tanu Singhal, Consultant, Paediatrics and Infectious Disease at Kokilaben Dhirubhai Ambani Hospital, speaks to hindustantimes.com on these and other issues.
Q: Does Delta Plus variant adversely affect vaccine efficacy?
Dr Singhal: The Delta Plus variant is a mutation in the Delta variant. The original Delta variant was first discovered in India and drove the second wave. It had acquired two new mutations - one was L452 R and other was E484 Q. We know that this variant is highly transmissible and possibly more virulent and less impacted by vaccines. This Delta Plus variant has been recently discovered and has another mutation - K417 N - which is also found in the beta and gamma variants which is the South American and the Brazilian variants but the practical experience with Delta Plus variant has been very less because there are only about 50-odd cases which have been sequenced in India so far. So, the first important point I would like to make is we don’t have sufficient knowledge about the transmissibility or the virulence or the immune escape properties of this Delta Plus variant. It has been hypothesised that because it has the K417 N mutation, which was also there in the Brazilian variant, it may escape vaccine induced immunity but there is no practical data to support it so far.
There is one woman in Rajasthan who was fully vaccinated yet got infected with Delta Plus variant but her disease was mild. So until now it has been discovered that while variants can cause breakthrough infections in vaccinated people overall the severity of the disease is milder.
Q: What happens if a recovered patient contracts the infection again, this time the Delta Plus variant?
Dr Singhal: Firstly, so far reinfections have been few. That means most of the patients who got infected in the first wave did not get infected in the second wave. So we know that prior infection with the other original virus did give long-lasting protection even against the delta variant. But we do not know how common that is going to be for reinfection with the delta plus. But until now all reinfections have been mild and not required hospitalisation unless person is vulnerable.
Q: What are the symptoms of infection with Delta Plus variant? Are they different from the Delta or Alpha variants?
Dr Singhal: We do not have data so far to establish that the symptoms are milder or more severe as compared to the delta variant.
Q: Is the third wave of Covid-19 going to be as devastating as the second one? Are we better prepared for it in terms of vaccines and oxygen supply?
Dr Singhal: We have sero-prevalence surveys that says about 60-70% of our population is immune which was about 25-30 per cent at the end of the first wave. Therefore, chances are that natural immunity is comparatively higher now than what it was after the first wave. Also we have vaccinations levels now which are much better. Hence, possibility of third wave being as severe as second wave is unlikely and it should rather be a smaller and less ferocious wave hopefully. This could change though if we have a new variant which emerges and is able to escape immunity provided by either previous infection or vaccination.
We will be better prepared to handle the third wave as compared to the second wave because what happened was after the first wave everybody became complacent as there were very few cases in the months that followed the first wave and people thought that India has achieved herd immunity and Indians are more immune than other people and Covid is gone from India and we did not build infrastructure which we should have between the first and second wave. So I think the message is gone through clear and authorities are trying to ramp up the infrastructure. Which is a good step and much desired for regular health services and also builds our preparedness for other future pandemics if they were to occur.
Q: How many waves are expected to hit before Covid-19 is declared under control? When are we expected to reach herd immunity?
Dr Singhal: No one has an answer to this question. But looking at the previous pandemics like Spanish flu, the Asian flu of 1957-58, the Hong Kong flu of 1967, or SARS or MERS outbreaks, or H1N1 flu of 2009, most pandemics have lasted for two years. As an extension to that, and also with the world achieving herd immunity and vaccinations increasing, I feel personally in another six month time we should have better control of this pandemic.