There may not be a third wave: Top virologist

With the emergence of the Delta Plus variant in a few countries and its threat looming large over India health experts and virologists have offered differing views on its likely impact While some experts feel the contagious strain will target even vaccinated people and children a top virologist says there are less chances of a third wave though he insists that being prepared is always betterA health worker takes a sample from a longdistance traveller at LTT on Monday PicSameer MarkandeAccording to Dr Subhash Hira Professor of Global Health at the University of WashingtonSeattle ldquoEarlier on in 2020 genome analyses had shown global dominance of SARSCoV2 variants as D614G which was responsible for waves 1 and wave2 of SARSCoV2 worldwide and paved the way for an appropriate universal vaccine However towards the end of 2020 new and genetically distinct phylogenetic clusters of SARSCoV2 were identified globally later designated as Variants of Concern VOCs and Variants of Interest VOIs by WHOrdquoDr Hira said the World Health Organisation WHO has categorised the five important Variants of Concern VOCs which have higher transmissibility and can reduce the effectiveness of existing treatment and vaccines as Alpha Beta Gamma Lambda and Delta He said that the third wave in the UK and Israel showed that almost 80 per cent and 95 per cent of new infections were caused by the Delta variants respectivelyldquoWhile D614G paved the way for universal vaccines the sudden accumulation of mutations in new VOCs such as the Delta having 68 mutations and Delta Plus having over 36 mutations in its sequences have led to reduced neutralisation by naturally or vaccineelicited antibodies The impact of the mutation clusters on reinfections and vaccine breakthrough infections caused due to reduced performance of different vaccines in terms of vaccine efficacy and neutralisation potential The latter changes in the virus coupled with the false sense of security of the host towards the vaccine to D614G strain and leading to lowering its guard to the barrier methods are the bases of scientists who are expecting the third wave by AugustSeptemberrdquo said Dr HiraDr Subhash Hira Professor of Global Health at the University of WashingtonSeattleAbout the potential third wave he said ldquoWith the emergence of new variants genomic surveillance has become a powerful tool to not only detect spread of the variants but also in understanding their infectivity Genome sequencing of Covid19 hot zones and animal reservoirs would be crucial for scientists and public health experts to prevent further epidemics Slogans such as lsquoWe are not safe until everyone is safersquo as equitable vaccine distribution is a humanitarian imperative Despite having a fully funded COVAX program in developing countries the health workers and people with underlying conditions will have no access to vaccines while only ten nations have administered 7537 of all vaccines This will lead to a disproportionate size of wave3 depending on the vaccine penetration in a countryrdquoDr Hira also emphasised ldquoNeurological manifestations are now widely being recognized in Covid19 patients infected with delta variants A wide array of manifestations ranging from encephalopathy insomnia ageusia and GuillainBarreacute syndrome have been reported Alzheimers diseaselike cognitive impairment has also been linked with delta variants Considering the role of VOCs in fuelling subsequent Covid19 infection waves it is imperative to preimplement necessary measures in controlling the Covid19 pandemicrdquoDoctors working in Covid19 hospitals say the third wave might hit Mumbai in the next few weeks citing the increase in number of cases and virulence load in the past few daysDr Rajesh Dhere dean of Covid Jumbo Centre BKC said they have increased the capacity to 2320 beds at their facility including 100 beds for the pediatric ward and 108 ICU beds ldquoFrom the pattern of Delta three variants in the UK and US it has been found to be over 60 per cent more virulent So the only solution is to maintain and follow Covid19 restrictions ndash wear a double mask maintain social distance and hand washrdquoNoted virologist differsWellknown virologist Dr Jacob John from Vellore had a different take He said ldquoVariants have different lsquotransmission efficienciesrsquo usually denoted by lsquobasic reproduction numberrsquo R0 The R0 of the lsquofounder variantrsquo Wuhan virus with D614G mutation was 2 which means one infected person would transmit infection to only 2 among all nonimmune social contacts That was pretty low transmission efficiency Delta variant has an R0 of 46 which means extremely high transmission efficiencyrdquoDr Rajesh Dere dean of BKC Jumbo Centre said theyrsquove got more bedsIn case of a higher R0 Dr John explained the outbreak can be sustained by a smaller number of susceptible populations ldquoWhen infection spreads to more persons children also get infected Within families the founder variant infected 3 out of ten household contacts whereas Delta infects 100 per cent So more children getting infected is a function of the virusrsquo transmission efficiencyrdquo said JohnHe added ldquoSince Indias second wave was predominantly due to Delta and as the wave is abating the same virus cannot cause the third wave If a variant with R0 more than 46 emerges we will have a third wave of low magnitude with the same proportions of children infected in the second wave but for a variant to better the R0 is very unlikely and for that reason a third wave is also very unlikelyrdquoStressing the need for expediting vaccination he said ldquoThe second wave is abating if we can speed up vaccination then even the natural susceptible peoples number will shrink further ensuring no third wave Getting prepared is wise expect the best but be prepared for the worstrdquoFiveNo of important VOCs categorised by WHO