February 3 coronavirus news

More than half of the population of the Indian capital region Delhi have been infected with Covid-19, according to a major survey conducted by the Delhi government.

“In the fifth serosurvey done, antibodies have been detected in 56.13% of the population. This was the largest survey in any state involving around 28,000 samples conducted from January 15 to 23," said Delhi Health Minister Satyendar Jain at a news conference on Tuesday.

"The last survey found 25-26% seroprevalence. This means Delhi is inching towards herd immunity," he added.

Daily cases and positivity rates are also declining, Jain said -- but he urged people not to let their guards down.

The Delhi region is home to more than 19 million people, according to government data.

India's cases: The country reported 11,039 new Covid-19 infections on Wednesday, according to the Indian Health Ministry. 

That raises the national total to 10,777,284 confirmed cases and 154,596 related deaths.

More than 4 million people have been vaccinated nationwide since the vaccination drive began on January 16, according to the ministry.

Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, says coronavirus vaccine doses available in the United States are expected to increase significantly over the next three months. 

"Right now, the real compelling thing is that the supply does not meet the demand. So, we've got to get more vaccine into people, and we've got to make sure that we use every possibility of getting doses out there."

As doses become available from companies such as Johnson & Johnson and Novavax, “things are going to get progressively better," he said.

Mass vaccination needed: About 70% to 85% of the population needs to be vaccinated in order to return to some sense of normalcy by the end of summer or beginning of fall, Fauci said.

But there's the danger that more transmissible variants of the coronavirus could become dominant in the US population. 

Many new recruits to the US Marines this past summer had evidence they had been infected with coronavirus -- a finding that supports the idea that healthy young people may be carrying and spreading the virus without ever knowing it, researchers reported Tuesday.

The team at the Naval Medical Research Center tested 3,249 Marine recruits who were quarantined between May and September, researchers reported in the journal Emerging Infectious Diseases. 

They found:

Young adults in the US have shown higher levels of Covid-19 antibodies than people of other ages -- but they are usually asymptomatic, and these cases go unnoticed, the researchers said. 

China’s Sinopharm Covid-19 vaccine can inactivate a worrying coronavirus variant first identified in South Africa, researchers from the Chinese Center for Disease Control and Prevention said Tuesday.

Their study is published online as a pre-print, meaning it has not been peer-reviewed, and includes few details.

Sinopharm’s vaccine, which the company says has been given to 10 million people across China, is a “live” virus vaccine -- meaning it's made using a whole virus that has been inactivated so it cannot cause disease.

The study: The team said they tested 12 samples taken from people who got the Sinopharm vaccine, and 12 samples from volunteers who received an experimental vaccine, against the variant virus.

Both vaccines elicited enough antibodies to neutralize the virus and overcome its mutation, they said.

The mutation, explained: The virus has a structure called the receptor binding domain, or RBD, which it uses to dock onto cells and infect them. The RBD is the mutated part of the new variant that makes it different from the original strand.

Many coronavirus vaccines, including those made by Pfizer and Moderna, specifically target the RBD -- but a live virus vaccine like Sinopharm's is less specific.

The biggest spreaders of coronavirus in the US are adults aged 20 to 49, and efforts to control the spread -- including vaccination -- should focus on that age group, researchers reported Tuesday.

Children and older adults accounted for very little spread, the researchers said -- suggesting that reopening schools may not contribute to spread, if transmission is controlled among younger adults, they said.

How they conducted the study: The team at Imperial College London used cell phone location data covering more than 10 million people and publicly available information on the spread of the virus to calculate which age groups were most responsible for the spread of the virus.

The results: They found that adults aged 20 to 49 accounted for about 72.2% of Covid-19 infections after schools reopened in October. Less than 5% of infections came from children, and less than 10% from teenagers.

And it might be adults aged 35 to 49 who are the biggest factor in driving the pandemic -- this group accounted for 41% of new transmissions through mid-August, compared to 35% for adults 20 to 34.

Containment efforts like mass vaccination programs aimed at this age group "could bring resurgent Covid-19 epidemics under control and avert deaths,” according to the study.

A large British study looking at coronavirus infections in real life confirms what lab experiments have shown: most people keep some antibodies to the virus for at least six months after recovery.

The study -- which included 20,000 people, plus their adult children and grandchildren -- also indicates 8.8% of the UK population had been infected with coronavirus by December -- but almost twice as many Blacks, 16.3%, had evidence of previous infection.

The study from UK Biobank, a biomedical database and research group, measured levels of previous infection in various population groups across the UK from the end of May to the beginning of December. It showed 99% of the participants who had previously tested positive for Covid-19 retained antibodies for three months after being infected and 88% had them for six months.

Antibodies were found in a greater proportion of younger people compared to older participants. The researchers said 13.5% of participants under 30 had detectable antibodies, while only 6.7% of those over 70 did. And 16.3% of Black volunteers in the study had antibodies to the virus, compared to 8.5% of White participants and 7.5% of participants of Chinese ethnicity.

Variants and antibodies: Allen said the team did not know whether the antibodies could provide protection against new variants of coronavirus. “I think it's just too early to tell about the level of protection,” she said. 

Rory Collins, head of the Nuffield Department of Population Health at the University of Oxford, said Tuesday that people who had previously been infected should still take care and obey social distancing guidelines.

A mutation that could allow Covid-19 to escape antibody protection has now been found in samples of a rapidly spreading strain in the UK, according to a report Monday by Public Health England.

The mutation, called E484K, was already part of the genetic signature of variants linked to South Africa and Brazil. 

According to the PHE report, the mutation has been newly detected in at least 11 samples of the UK's B.1.1.7 strain. It also appears some of these samples may have acquired this mutation independently, instead of spreading from a single case.

This could mean a variant already known to be more transmissible also risks becoming somewhat resistant to the immune protection offered by vaccines, or more likely to cause reinfection among people who were previously infected, experts say. 

He added the new finding is also something to keep monitoring in the United States, where efforts to look for variants through genetic sequencing have lagged behind the UK. The fact that we've only seen this in the UK "may be a result of their robust genomic surveillance program," Fauver said. 

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More than 100,000 people have died of Covid-19 in the United States so far this year, according to Johns Hopkins University data.

Since January 1, the US reported at least 100,317 Covid-19 deaths, bringing the total number of reported deaths in the US since the start of the pandemic to at least 446,689 by Tuesday evening.

The first Covid-19 related death came on February 29, 2020, in Washington state. Later in the spring, two earlier deaths in California were posthumously confirmed to be of Covid-19.

The US has had more Covid-19 deaths than any other country, JHU data shows. Brazil has tallied over 200,000 deaths. Mexico, India and the United Kingdom have all reported over 100,000 deaths.

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Those who had Covid-19 could get reinfected if the variants become dominant, Fauci says

After criticism last year for an early rollout, Russia's Sputnik V vaccine is 91.6% effective against symptomatic Covid-19 and 100% effective against severe and moderate disease, according to an interim analysis of the vaccine's Phase 3 trial results.

The preliminary findings were published in The Lancet on Tuesday and are based on data gathered from 19,866 participants, of which around three-quarters (14,964) received two doses of the vaccine and a quarter (4,902) were given a placebo.

Sixteen cases of symptomatic Covid-19 were confirmed in the vaccine group 21 days after participants received the first vaccine dose. Sixty-two cases were found in the placebo group -- equating to an efficacy of 91.6%.

The trial included 2,144 people over the age of 60 and a sub-analysis conducted on this group revealed the vaccine was well tolerated and had a similar efficacy of 91.8%.

The team also analyzed the efficacy of the vaccine against severe and moderate Covid-19 disease and 21 days after the first dose no severe or moderate cases were reported in the vaccinated group, while 20 were reported in the placebo group.

Serious adverse events were also rare and none was considered to be associated with vaccination. The majority of side-effects that were reported were mild, such as pain at the injection site, flu like symptoms and low energy levels, according to the study.

The analysis includes only symptomatic cases of Covid-19, however, and the authors note more research is needed to understand the vaccine's efficacy against asymptomatic Covid-19, transmission and how long protection may last.

The majority of participants in the trial were also White so further research is needed to confirm the results across other ethic groups. The trial is also ongoing and is aiming to include a total of 40,000 participants.

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