Lancet study casts doubt on COVID-19 herd immunity feasibility


PTI, Jul 7, 2020, 4:47 PM IST

New Delhi: A Spanish study published in The Lancet journal has cast doubt over the feasibility of herd immunity when enough people become infected with a virus to stop its spread as a way of tackling the COVID-19 pandemic.

For herd immunity to work, at least 70 percent of a population needs to be immune to protect the uninfected people, experts say.

The study of over 60,000 people estimates that around just 5 percent of the Spanish population has developed antibodies, according to the researchers, including those from the National Centre for Epidemiology, Spain.

The aim of the population-based study was to estimate the seroprevalence of the level of a pathogen in a population, as measured in blood serum of SARS-CoV-2 infection in Spain at the national and regional levels.

“About 35,883 households were selected from municipal rolls using two-stage random sampling stratified by province and municipality size,” the researchers said.

From April 27 to May 11, 61,075 participants answered a questionnaire on a history of symptoms compatible with COVID-19 and risk factors, among others.

“Prevalences of IgG antibodies were adjusted using sampling weights and post-stratification to allow for differences in non-response rates based on age group, sex, and census-tract income,” the researchers wrote in the medical journal.

“Using results for both tests, we calculated a seroprevalence range maximizing either specificity (positive for both tests) or sensitivity (positive for either test),” they said.

The researchers noted that seroprevalence was 5 percent by the point-of-care test and 4·6 percent by immunoassay, with no differences by sex and lower seroprevalence in children younger than 10 years.

“There was substantial geographical variability, with higher prevalence around Madrid (over 10 percent) and lower in coastal areas (less than 3 percent),” they said.

The findings suggest that majority of the Spanish population is seronegative to SARS-CoV-2 infection, even in hotspot areas, according to the researchers.

“Most PCR-confirmed cases have detectable antibodies, but a substantial proportion of people with symptoms compatible with COVID-19 did not have a PCR test and at least a third of infections determined by serology were asymptomatic,” the researchers wrote in the journal.

“These results emphasize the need for maintaining public health measures to avoid a new epidemic wave,” they said.

Udayavani is now on Telegram. Click here to join our channel and stay updated with the latest news.

Top News

2 detained for killing tailor in Rajasthan’s Udaipur

Stinking toilets on trains: Railways deploys senior officials for inspection

Taapsee Pannu on teaming up with SRK in ‘Dunki’: It’s a golden opportunity

Eoin Morgan retires, draws curtains on glorious international career

Udupi: Youth enacts kidnap drama to extort Rs 5 Lakhs; ends up behind bars

Tailor murdered over ‘insult to Islam’, tension in Udaipur

No hike in electricity tariff for consumers for now: Min Sunil Kumar issues clarification


Related Articles More

‘Action to be taken against those violating mask rule’

Technical glitch hits compiling of Covid-19 data base for 2nd day

858 COVID-19 cases, 1 death in Karnataka

Mandaviya to chair crucial meeting with experts on rising COVID-19 cases

Karnataka reports 623 COVID-19 cases, 1 death

MUST WATCH

Bride breaks down after receiving wax statue of her late father as a gift. Video divides Internet

House Caught Fire at Kumta

Major Road Mishap at Hunasur, 1 killed and 4 injured

Vijayapura And Dotihal Tradition : farmers Celebrating Amavasya

Khadar speaks about developmental activities


Latest Additions

Zubair’s ‘objectionable’ tweet of 2018 led to Twitter storm with ‘hate’ speeches: Delhi Police

2 detained for killing tailor in Rajasthan’s Udaipur

Maha CM Thackeray chairs cabinet meeting, first after taking away rebel ministers’ portfolios

Stinking toilets on trains: Railways deploys senior officials for inspection

Taapsee Pannu on teaming up with SRK in ‘Dunki’: It’s a golden opportunity

Thanks for visiting Udayavani

You seem to have an Ad Blocker on.
To continue reading, please turn it off or whitelist Udayavani.