Delta variant can be transmitted by the fully vaccinated at home: Lancet study

Fully vaccinated people can contract and pass on Delta variant of SARSCoV2 the virus that causes Covid19 in household settings but at lower rates than unvaccinated people according to a study published in The Lancet Infectious Diseases journalResearchers led by Imperial College London UK found that vaccinated people clear the infection more quickly but the peak viral load among them is similar to that seen in unvaccinated individuals which may explain why they can still readily pass on the virus at homeThe researchers noted that most Covid19 transmission is known to occur in households yet there is limited data on the risk of transmission of the Delta variant from vaccinated people with asymptomatic or mild infections in the communityVaccines are critical to controlling the pandemic as we know they are very effective at preventing serious illness and death from Covid19 said Professor Ajit Lalvani of Imperial College London who coled the studyHowever our findings show that vaccination alone is not enough to prevent people from being infected with the Delta variant and spreading it in household settings Lalvani addedAlso Read Covid19 Experts warn Mumbaikars about new AY42 subvariantThe researchers noted that the transmission between vaccinated people makes it essential for unvaccinated people to get immunised to protect themselves from acquiring infection and severe Covid19 especially as more people will be spending time inside in close proximity during the winter monthsThe study enrolled 621 participants identified by the UK contact tracing system between September 2020 and September 2021All participants had mild Covid19 illness or were asymptomatic They had daily PCR tests to detect infection regardless of whether or not they had symptomsThe researchers performed PCR tests on swab samples provided daily by each participant for 14iquest20 days Changes over time in viral load the amount of virus in a persons nose and throat were estimated by modelling PCR dataA total of 205 household contacts of Delta variant index cases were identified of whom 53 tested positive for Covid19Among vaccinated contacts infected with the Delta variant the median length of time since vaccination was 101 days compared with 64 days for uninfected contacts the researchers saidThis suggests that the risk of infection increased within three months of receiving a second vaccine dose likely due to waning protective immunity they saidThe authors point to vaccine waning as important evidence for all eligible people to receive booster shotsA total of 133 participants had their daily viral load trajectories analysed of whom 49 had preAlpha variant and were unvaccinated 39 had Alpha and were unvaccinated 29 had Delta and were fully vaccinated and 16 had Delta and were unvaccinatedThe study found that the viral load declined more rapidly among vaccinated people infected with the Delta variant compared with unvaccinated people with Delta Alpha or preAlphaHowever the authors note that vaccinated people did not record a lower peak viral load than unvaccinated people which may explain why the Delta variant can still spread despite vaccination as people are most infectious during the peak viral load phaseUnderstanding the extent to which vaccinated people can pass on the Delta variant to others is a public health priority said Anika Singanayagam colead author of the studyBy carrying out repeated and frequent sampling from contacts of Covid19 cases we found that vaccinated people can contract and pass on infection within households including to vaccinated household members Singanayagam saidThe findings suggest that continued public health and social measures to curb transmission such as mask wearing social distancing and testing remain important even in vaccinated individualsThe authors acknowledge some limitations to their study Due to the nature of UK symptomsbased community testing only contacts of symptomatic index cases were recruited the researchers saidAs the study was undertaken when infection was circulating widely it cannot be excluded that another household member may already have been infected and transmitted Covid19 to the index case they addedThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever