More unvaccinated U.S. adolescents hospitalized; myocarditis may be rare vaccine side effect in teens

By Nancy Lapid

(Reuters) – The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

COVID-19 hospitalizations up among U.S. adolescents

COVID-19 hospitalizations rose among U.S. adolescents in March and April, and nearly a third of those hospitalized needed intensive care, according to data from more than 250 hospitals in 14 states released by the Centers for Disease Control and Prevention (CDC) on Friday. “Rates of COVID-19-associated hospitalization among adolescents also exceeded historical rates of seasonal influenza-associated hospitalization during comparable periods,” researchers reported in the CDC’s Morbidity and Mortality Weekly Report. The hospitals reported a total of 204 adolescents hospitalized for COVID-19 in March and April. “Until they are fully vaccinated, adolescents should continue to wear masks and take precautions when around others who are not vaccinated to protect themselves, and their family, friends, and community,” CDC Director Rochelle Walensky said in a statement on Friday. “I ask parents, relatives and close friends to join me and talk with teens about the importance of these prevention strategies and to encourage them to get vaccinated.”

Heart inflammation may be rare vaccine side effect in teens

Temporary heart inflammation may be a rare side effect of the Pfizer/BioNTech COVID-19 vaccine in teenagers, according to pediatricians who reported on seven cases from across the United States. The previously healthy adolescents – all boys – developed chest pain within four days after their second dose. MRI exams showed myocarditis, or heart muscle inflammation. “Fortunately, none of our patients was critically ill,” the authors reported on Friday in Pediatrics. The boys’ symptoms resolved “rapidly” with medication. Measures of cardiac status had returned to normal at check-ups performed after one-to-three weeks. Myocarditis is a known rare adverse event following other vaccinations, the authors noted. There is no proof, however, that the vaccine caused these cases. “So far, over 2.2 million teenagers (aged) 16-17 have already received 2 doses of Pfizer vaccine, and over 3 million kids 12-15 years old have received dose #1,” said coauthor Dr. Judy Guzman-Cottrill of Oregon Health & Science University. “These are huge, very reassuring denominators.” COVID-19 itself can cause myocarditis, she noted. “After looking at the risks and benefits, the data support getting kids vaccinated.”

Measuring longer-lasting COVID-19 immunity feasible

Along with testing for antibody levels after COVID-19 or vaccination to gauge a person’s immunity to the virus, measuring the response of the immune system’s T cells could provide important information, according to researchers based at Cardiff University. While antibody levels wane over time, T cell responsiveness can last for months or years. But T cells have been harder to measure in cost-effective ways. Adapting a method widely employed to measure immune responses to other types of infections, the researchers took blood samples from adults and children and stimulated T cells with small proteins specific to the SARS-CoV-2 virus. T cells that recognize these proteins, because the person has been previously infected or vaccinated, “are triggered to produce chemicals like interferon which can be easily measured,” said study coauthor Andrew Godkin. The results were about 96% accurate, researchers reported on Tuesday on medRxiv ahead of peer review. “The test is very sensitive and seems to be accurate at identifying people previously exposed to the virus,” Godkin said. “The test is widely available, easy to employ, and should play a very useful role in monitoring this pandemic.”

Virus unlikely to insert genetic fragments into patients’ genetic code

A new study refutes the controversial claim made by researchers last month in PNAS that small fragments of genetic instructions from the coronavirus became integrated into the genome of infected cells, in test tube experiments. In principle, coronavirus RNA generated by such integrated snippets, while probably not harmful, might cause positive COVID-19 PCR tests long after a patient has recovered, the authors of that study said. But when researchers in Australia sought to find signs of SARS-CoV-2 genetic code integrated into the DNA of infected cells, they could not find any. “This was despite using the same sequencing technology and cell type (as in the PNAS study) and performing substantially more DNA sequencing,” said Geoffrey Faulkner of the University of Queensland. The new finding were posted on Sunday on bioRxiv ahead of peer review. The researchers did find copies of hepatitis B virus integrated into liver tissue, and copies of other DNA elements integrated into the cells they experimented with, “suggesting our approach would have found SARS-CoV-2 copies” if they were present, he said. His team agrees with others who suggest the PNAS findings may have reflected unintended effects of experimental methods. “We think SARS-CoV-2 integration into DNA is possible in human cells even if it is likely to be incredibly rare in patients,” Faulkner said.

(Reporting by Nancy Lapid and Christine Soares; Editing by Bill Berkrot)

Booster shots may be needed within a year after COVID-19 vaccinations -U.S. official

By Reuters Staff

(Reuters) – The United States is preparing for the possibility that a booster shot will be needed between nine to 12 months after people are initially vaccinated against COVID-19, a White House official said on Thursday.

While the duration of immunity after vaccination is being studied, booster vaccines could be needed, David Kessler, chief science officer for President Joe Biden’s COVID-19 response task force told a congressional committee meeting.

“The current thinking is those who are more vulnerable will have to go first,” Kessler said.

Initial data has shown that vaccines from Moderna Inc and partners Pfizer Inc and BioNTech SE retain most of their effectiveness for at least six months.

Even if that protection lasts far longer, experts have said that rapidly spreading variants of the coronavirus and others that may emerge could lead to the need for regular booster shots – such as with annual flu shots.

The United States is also tracking infections in people who have been fully vaccinated, Rochelle Walensky, director of the U.S. Centers of Disease Control and Prevention told the House subcommittee hearing.

Of 77 million people vaccinated in the United States, there have been 5,800 such breakthrough infections, Walensky said, including 396 people who required hospitalization and 74 who died.

Walensky said some of these infections have occurred because the vaccinated person did not mount a strong immune response. But the concern is that in some cases, they are occurring in people infected by more contagious virus variants.

Exclusive: Regular booster vaccines are the future in battle with COVID-19 virus, top genome expert says

By Guy Faulconbridge

CAMBRIDGE, England (Reuters) – Regular booster vaccines against the novel coronavirus will be needed because of mutations that make it more transmissible and better able to evade human immunity, the head of Britain’s effort to sequence the virus’s genomes told Reuters.

The novel coronavirus, which has killed 2.65 million people globally since it emerged in China in late 2019, mutates around once every two weeks, slower than influenza or HIV, but enough to require tweaks to vaccines.

Sharon Peacock, who heads COVID-19 Genomics UK (COG-UK) which has sequenced nearly half of all the novel coronavirus genomes so far mapped globally, said international cooperation was needed in the “cat and mouse” battle with the virus.

“We have to appreciate that we were always going to have to have booster doses; immunity to coronavirus doesn’t last forever,” Peacock told Reuters at the non-profit Wellcome Sanger Institute’s 55-acre campus outside Cambridge.

“We already are tweaking the vaccines to deal with what the virus is doing in terms of evolution – so there are variants arising that have a combination of increased transmissibility and an ability to partially evade our immune response,” she said.

Peacock said she was confident regular booster shots – such as for influenza – would be needed to deal with future variants but that the speed of vaccine innovation meant those shots could be developed at pace and rolled out to the population.

COG-UK was set up by Peacock, a professor at Cambridge, exactly a year ago with the help of the British’s government’s chief scientific adviser, Patrick Vallance, as the virus spread across the globe to Britain.

The consortium of public health and academic institutions is now the world’s deepest pool of knowledge about the virus’s genetics: At sites across Britain, it has sequenced 349,205 genomes of the virus out of a global effort of around 778,000 genomes.

On the intellectual frontline at the Wellcome Sanger Institute, hundreds of scientists – many with PhDs, many working on a voluntary basis and some listening to heavy metal or electronic beats – work seven days a week to map the virus’s growing family tree for patterns of concern.

Wellcome Sanger Institute has sequenced over half of the UK total sequenced genomes of the virus after processing 19 million samples from PCR tests in a year. COG-UK is sequencing around 30,000 genomes per week – more than the UK used to do in a year.

MUTATION LEADERBOARD

Three main coronavirus variants – which were first identified in Britain (known as B.1.1.7), Brazil (known as P1) and South Africa (known as B.1.351) – are under particular scrutiny.

Peacock said she was most worried about B.1.351.

“It is more transmissible, but it also has a change in a gene mutation, which we refer to as E484K, which is associated with reduced immunity – so our immunity is reduced against that virus,” Peacock said.

With 120 million cases of COVID-19 around the world, it is getting hard to keep track of all the alphabet soup of variants, so Peacock’s teams are thinking in terms of “constellations of mutations”.

“So a constellation of mutations would be like a leaderboard if you like – which mutations in the genome that we’re particularly concerned about, the E484K is must be one of the top of the leaderboard,” she said.

“So we’re developing our thinking around that leaderboard to think, regardless of the background and lineage, about what mutations or constellation of mutations are going to be important biologically and different combinations that may have slightly different biological effects.”

Peacock, though, warned of humility in the face of a virus that has brought so much death and economic destruction.

“One of the things that the virus has taught me is that I can be wrong quite regularly – I have to be quite humble in the face of a virus that we know very little about still,” she said.

“There may be a variant out there that we haven’t even discovered yet.”

There will, though, be future pandemics.

“I think its inevitable that we will have another virus emerge that is of concern. What I hope is that having learned what we have in this global pandemic, that we will be better prepared to detect it and contain it.”

(Reporting by Guy Faulconbridge; Editing by Kate Holton and Philippa Fletcher)

Spain close to vaccinating all nursing-home residents, on track for summer goals

By Nathan Allen

MADRID (Reuters) – Spain has given a full two-shot course of coronavirus vaccines to almost all its elderly nursing-home residents, the FED care-home association said on Friday, restoring some sense of security to the most vulnerable section of the population.

Separately, Prime Minister Pedro Sanchez said the country, which has administered 2.8 million doses and fully inoculated 1.14 million people, was on track to vaccinate 20 million people in the first half of 2021 out of a population of 47 million.

Nearly 43,000 care-home residents died of COVID-19 or suspected infection in the devastating March-May first wave of contagion, and prosecutors are investigating more than 200 cases of potential criminal negligence at such homes.

But more than 97% of residents have now been vaccinated across Spain’s 17 regions, according to the FED, putting nursing homes among the country’s safest places.

“They are very positive data that allow us to be optimistic about the future,” said FED’s president Ignacio Fernandez Cid. “Immunity will allow us to gradually return to the longed-for lost normality.”

Health Emergency Chief Fernando Simon said earlier this week that for the first time since the start of the pandemic, people over 65 who live in care homes have a lower rate of infection than those who live outside, supporting the thesis, if indirectly, that the vaccines are having an effect.

Frontline medics and care workers are the only people under 65 to receive a vaccine so far.

Spain will now give shots made by Pfizer-BioNTech and Moderna to people over 80, while AstraZeneca’s drug will go to key workers under 55.

With a third wave quickly receding, Spain’s two-week infection rate hit 321 cases per 100,000 people on Thursday, from almost 900 cases at the end of January, prompting several regions to relax measures.

Madrid on Thursday pushed its curfew back an hour to 11 p.m. and on Friday lifted travel restrictions on 31 neighborhoods.

(Reporting by Nathan Allen, editing by Andrei Khalip)

COVID-19 infection gives some immunity, but virus can still be spread, study finds

By Kate Kelland

LONDON (Reuters) – People who have had COVID-19 are highly likely to have immunity to it for at least five months, but there is evidence that those with antibodies may still be able to carry and spread the virus, a study of British healthcare workers has found.

Preliminary findings by scientists at Public Health England (PHE) showed that reinfections in people who have COVID-19 antibodies from a past infection are rare – with only 44 cases found among 6,614 previously infected people in the study.

But experts cautioned that the findings mean people who contracted the disease in the first wave of the pandemic in the early months of 2020 may now be vulnerable to catching it again.

They also warned that people with so-called natural immunity – acquired through having had the infection – may still be able carry the SARS-CoV-2 coronavirus in their nose and throat and could unwittingly pass it on.

“We now know that most of those who have had the virus, and developed antibodies, are protected from reinfection, but this is not total and we do not yet know how long protection lasts,” said Susan Hopkins, senior medical adviser at PHE and co-leader of the study, whose findings were published on Thursday.

“This means even if you believe you already had the disease and are protected, you can be reassured it is highly unlikely you will develop severe infections. But there is still a risk you could acquire an infection and transmit (it) to others.”

MAJOR IMPLICATIONS

Experts not directly involved in the research, which is known as the SIREN study, urged people to note its key findings.

“These data reinforce the message that, for the time being, everyone is a potential source of infection for others and should behave accordingly,” said Eleanor Riley, a professor of immunology and infectious disease at Edinburgh University.

Simon Clarke, an associate professor in cellular microbiology at Reading University, said the study “has major implications for how we can get out of the current crisis”.

“This means that the vast majority of the population will either need to have natural immunity or have been immunized for us to fully lift restrictions on our lives, unless we are prepared to see many more people being infected and dying from COVID-19,” he said.

PHE said in a statement that the study had not been able to explore antibody or other immune responses to the COVID-19 vaccines being rolled out in Britain. Vaccine effects would be studied as part of SIREN later this year, it said.

The SIREN study involves tens of thousands of healthcare workers in Britain who have been tested regularly since June for new COVID-19 infections as well as for the presence of antibodies.

Between June 18 and Nov. 24, scientists found 44 potential reinfections – two “probable” and 42 “possible” – among 6,614 participants who had tested positive for antibodies. This represents an 83% rate of protection from reinfection, they said.

The researchers said they would continue to follow the participants to see if this natural immunity might last longer than five months in some. But they said early evidence from the next stage of the study suggested some people with immunity could still carry high levels of virus.

(Reporting by Kate Kelland; Editing by Mark Heinrich, Robert Birsel)

Scientists see downsides to top COVID-19 vaccines from Russia, China

By Allison Martell and Julie Steenhuysen

TORONTO/CHICAGO (Reuters) – High-profile COVID-19 vaccines developed in Russia and China share a potential shortcoming: They are based on a common cold virus that many people have been exposed to, potentially limiting their effectiveness, some experts say.

CanSino Biologics’ vaccine, approved for military use in China, is a modified form of adenovirus  type 5, or Ad5. The company is in talks to get emergency approval in several countries before completing large-scale trials, the Wall Street Journal reported last week.

A vaccine developed by Moscow’s Gamaleya Institute, approved in Russia earlier this month despite limited testing, is based on Ad5 and a second less common adenovirus.

“The Ad5 concerns me just because a lot of people have immunity,” said Anna Durbin, a vaccine researcher at Johns Hopkins University. “I’m not sure what their strategy is … maybe it won’t have 70% efficacy. It might have 40% efficacy, and that’s better than nothing, until something else comes along.”

Vaccines are seen as essential to ending the pandemic that has claimed over 845,000 lives worldwide. Gamaleya has said its two-virus approach will address Ad5 immunity issues.

Both developers have years of experience and approved Ebola vaccines based on Ad5. Neither CanSino nor Gamaleya responded to requests for comment.

Researchers have experimented with Ad5-based vaccines against a variety of infections for decades, but none are widely used. They employ harmless viruses as “vectors” to ferry genes from the target virus – in this case the novel coronavirus – into human cells, prompting an immune response to fight the actual virus.

But many people already have antibodies against Ad5, which could cause the immune system to attack the vector instead of responding to the coronavirus, making these vaccines less effective.

Several researchers have chosen alternative adenoviruses or delivery mechanisms. Oxford University and AstraZeneca based their COVID-19 vaccine on a chimpanzee adenovirus, avoiding the Ad5 issue. Johnson & Johnson’s candidate uses Ad26, a comparatively rare strain.

Dr. Zhou Xing, from Canada’s McMaster University, worked with CanSino on its first Ad5-based vaccine, for tuberculosis, in 2011. His team is developing an inhaled Ad5 COVID-19 vaccine, theorizing it could circumvent pre-existing immunity issues.

“The Oxford vaccine candidate has quite an advantage” over the injected CanSino vaccine, he said.

Xing also worries that high doses of the Ad5 vector in the CanSino vaccine could induce fever, fueling vaccine skepticism.

“I think they will get good immunity in people that don’t have antibodies to the vaccine, but a lot of people do,” said Dr. Hildegund Ertl, director of the Wistar Institute Vaccine Center in Philadelphia.

In China and the United States, about 40% of people have high levels of antibodies from prior Ad5 exposure. In Africa, it could be as high as 80%, experts said.

HIV RISK

Some scientists also worry an Ad5-based vaccine could increase chances of contracting HIV.

In a 2004 trial of a Merck & Co Ad5-based HIV vaccine, people with pre-existing immunity became more, not less, susceptible to the virus that causes AIDS.

Researchers, including top U.S. infectious diseases expert Dr. Anthony Fauci, in a 2015 paper, said the side effect was likely unique to HIV vaccines. But they cautioned that HIV incidence should be monitored during and after trials of all Ad5-based vaccines in at-risk populations.

“I would be worried about the use of those vaccines in any country or any population that was at risk of HIV, and I put our country as one of them,” said Dr. Larry Corey, co-leader of the U.S. Coronavirus Vaccine Prevention Network, who was a lead researcher on the Merck trial.

Gamaleya’s vaccine will be administered in two doses: The first based on Ad26, similar to J&J’s candidate, and the second on Ad5.

Alexander Gintsburg, Gamaleya’s director, has said the two-vector approach addresses the immunity issue. Ertl said it might work well enough in individuals who have been exposed to one of the two adenoviruses.

Many experts expressed skepticism about the Russian vaccine after the government declared its intention to give it to high-risk groups in October without data from large pivotal trials.

“Demonstrating safety and efficacy of a vaccine is very important,” said Dr. Dan Barouch, a Harvard vaccine researcher who helped design J&J’s COVID-19 vaccine. Often, he noted, large-scale trials “do not give the result that is expected or required.”

(Additional reporting by Christine Soares in New York, Kate Kelland in London, Polina Ivanova in Moscow and Roxanne Liu in Beijing; Editing by Caroline Humer and Bill Berkrot)

First U.S. COVID-19 reinfection case identified in Nevada study

By Deena Beasley

(Reuters) – Researchers for the first time have identified someone in the United States who was reinfected with the novel coronavirus, according to a study that has not yet been reviewed by outside experts.

The report, published online, describes a 25-year-old man living in Reno, Nevada, who tested positive for the virus in April after showing mild illness. He got sick again in late May and developed more severe COVID-19, the disease caused by the virus.

Cases of presumed reinfection have cropped up in other parts of the world, but questions have arisen about testing accuracy. Earlier this week, University of Hong Kong researchers reported details of a 33-year-old man who had recovered in April from a severe case of COVID-19 and was diagnosed four months later with a different strain of the virus.

Researchers at the University of Nevada, Reno School of Medicine and the Nevada State Public Health Laboratory said they were able to show through sophisticated testing that the virus associated with each instance of the Reno man’s infection represented genetically different strains.

They emphasized that reinfection with the virus is probably rare, but said the findings imply that initial exposure to the virus may not result in full immunity for everyone.

(Reporting by Deena Beasley; Editing by Dan Grebler)

New York City ahead of curve on COVID-19, but faces risks going into fall: experts

By Carl O’Donnell

NEW YORK (Reuters) – New York City, once an epicenter of the novel coronavirus outbreak, has managed to contain the virus as it reopens, but faces risks of an uptick in cases in the fall, public health experts told Reuters.

The city’s success comes from a mix of high rates of compliance with local and federal public health guidance and also substantial immunity among the general population, a result of the severity of the outbreak in March and April, according to public health experts based in New York City.

“There was an alignment in New York with the state government, the healthcare system and the media on what to do – namely, lock everything down,” said Mark Jarrett, chief quality officer at Northwell Health. “The lockdown didn’t please everyone but was really well accepted.”

That contrasts with other parts of the country, where political opposition to mask wearing and lockdowns is more widespread, Jarrett added.

The rate of contagion also declined more quickly because the initial outbreak left between 25% and 50% of New Yorkers with some level of immunity, said Maria Lima, associate dean for research at the City University of New York School of Medicine.

New York is at risk for an uptick in cases as schools reopen and cold weather pushes more people indoors, the experts said.

“The big challenge is schools reopening, recreating that density anew,” which had been reduced by social distancing, said Troy Tassier, a professor of economics at Fordham University who specializes in epidemiology.

After peaking in early April at a seven day average of more than 5,000 cases per day, New York City has reduced its daily case count to an average of less than 200, according to city data.

The percentage of people tested who turned out to have the virus declined from around 70% in late March to less than 1%, and confirmed deaths have declined from over 500 per day in April to the low single digits.

The United States as a whole continues to struggle to contain the virus, clocking upwards of 45,000 cases per day. Total cases have surpassed 5.5 million and more than 170,000 people have died.

(Reporting by Carl O’Donnell in New York; Editing by Daniel Wallis)

Monkeys infected with COVID-19 develop immunity in studies, a positive sign for vaccines

By Julie Steenhuysen

CHICAGO (Reuters) – Two studies in monkeys published on Wednesday offer some of the first scientific evidence that surviving COVID-19 may result in immunity from reinfection, a positive sign that vaccines under development may succeed, U.S. researchers said on Wednesday.

Although scientists have assumed that antibodies produced in response to the new coronavirus virus are protective, there has been scant scientifically rigorous evidence to back that up.

In one of the new studies, researchers infected nine monkeys with COVID-19, the illness caused by the novel coronavirus. After they recovered, the team exposed them to the virus again and the animals did not get sick.

The findings suggest that they “do develop natural immunity that protects against re-exposure,” said Dr. Dan Barouch, a researcher at the Center for Virology and Vaccine Research at Harvard’s Beth Israel Deaconness Medical Center in Boston, whose studies were published in the journal Science.

“It’s very good news,” Barouch said.

Several research teams have released papers – many of them not reviewed by other scientists – suggesting that a vaccine against the virus would be effective in animals.

In the second study, Barouch and colleagues tested 25 monkeys with six prototype vaccines to see if antibodies produced in response were protective.

They then exposed these monkeys and 10 control animals to SARS-CoV-2, the official name of the novel coronavirus.

All of the control animals showed high degrees of virus in their noses and lungs, but in the vaccinated animals, “we saw a substantial degree of protection,” Barouch said. Eight of the vaccinated animals were completely protected.

These studies, which have been peer reviewed, do not prove that humans develop immunity or how long it might last, but they are reassuring.

“These data will be seen as a welcome scientific advance,” Barouch said.

(Reporting by Julie Steenhuysen; Editing by Bill Berkrot)

Most COVID-19 patients get antibodies but immunity unclear: UK official

LONDON (Reuters) – Studies in Britain show that most people who have had COVID-19 develop antibodies, England’s deputy chief medical officer Jonathan Van-Tam said on Monday, but it was too early to say whether this gave them immunity.

“The overwhelming majority of people so far called back who’ve had definite COVID-19 infection have got antibodies in their blood stream,” Van-Tam said at daily news conference.

“By and large the signal is that people get antibodies. The next question is, do those antibodies protect you from further infections. And we just haven’t had this disease around … for long enough to know the answers to that with any surety.”

Health Secretary Matt Hancock added that the government was in discussions with Swiss pharmaceutical firm Roche over antibody testing.

(Reporting by William James and Andy Bruce; writing by Alistair Smout; editing by Estelle Shirbon)