Tag Archives: booster vaccines

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.

Analysis-In mutant variants, has the coronavirus shown its best tricks?

By Kate Kelland and Julie Steenhuysen

LONDON/CHICAGO (Reuters) – The rapid rise in different parts of the world of deadly, more infectious coronavirus variants that share new mutations is leading scientists to ask a critical question – has the SARS-CoV-2 virus shown its best cards?

New variants first detected in such far-flung countries as Brazil, South Africa and Britain cropped up spontaneously within a few months late last year. All three share some of the same mutations in the important spike region of the virus used to enter and infect cells.

These include the E484k mutation, nicknamed “Eek” by some scientists for its apparent ability to evade natural immunity from previous COVID-19 infection and to reduce protection offered by current vaccines – all of which target the spike protein.

The appearance of similar mutations, independent of one another, springing up in different parts of the globe shows the coronavirus is undergoing “convergent evolution,” according to a dozen scientists interviewed by Reuters.

Although it will continue to mutate, immunologists and virologists said they suspect this coronavirus has a fixed number of moves in its arsenal.

The long-term impact for the virus’ survival, and whether a limit on the number of mutations makes it less dangerous, remains to be seen.

“It is plausible that this virus has a relatively limited number of antibody escape mutations it can make before it has played all of its cards, so to speak,” said Shane Crotty, a virologist at the La Jolla Institute for Immunology in San Diego.

That could enable drugmakers to stay on top of the virus as they develop booster vaccines directly targeting current variants, while governments struggle to tame a pandemic that has killed nearly 3 million people.

The idea that the virus could have a limited number of mutations has been circulating among experts since early February, and gathered momentum with the posting of a paper showing the spontaneous appearance of seven variants in the United States, all in the same region of the spike protein.

EVOLUTION, IN REAL TIME

The process of different species independently evolving the same traits that improve survival odds is central to evolutionary biology. The vast scope of the coronavirus pandemic – with 127.3 million infections globally – allows scientists to observe it in real time.

“If you wanted to sort of write a little textbook about viral evolution, it’s happening right now,” Dr. Francis Collins, a geneticist and director of the U.S. National Institutes of Health, said in an interview.

Scientists saw the process on a smaller scale in 2018 as a dangerous H7N9 bird flu virus in China appeared to begin adapting to human hosts. But no pathogen has evolved under such global scrutiny as SARS-CoV-2.

Wendy Barclay, a virologist and professor at Imperial College London and a member of a scientific advisory panel to the UK government, said she is struck by the “amazing amount of convergent evolution we’re seeing” with SARS-CoV-2.

“There are these infamous mutations – E484K, N501Y and K417N – which all three variants of concern are accumulating. That, added together, is very strong biology that this is the best version of this virus in the given moment,” Barclay said.

It’s not that this coronavirus is especially clever, scientists said. Each time it infects people it makes copies of itself, and with each copy it can make mistakes. While some mistakes are insignificant one-offs, the ones that give the coronavirus a survival advantage tend to persist.

“If it keeps happening over and over again, it must be providing some real growth advantage to this virus,” Collins said.

Some specialists believe the virus may have a limited number of mutations it can sustain before compromising its fitness – or changing so much it is no longer the same virus.

“I don’t think it’s going to reinvent itself with extra teeth,” said Ian Jones, a professor of virology at Britain’s University of Reading.

“If it had an unlimited number of tricks…we would see an unlimited number of mutants, but we don’t,” said Michel Nussenzweig, an immunologist at Rockefeller University in New York.

CAUTIOUS OPTIMISM

Scientists remain cautious, however, and say predicting how a virus will mutate is challenging. If there are limits on how the coronavirus can evolve, that would simplify things for vaccine developers.

Novavax Inc is adapting its vaccine to target the South African variant that in lab tests appeared to render current vaccines less effective. Chief Executive Stan Erck said the virus can only change so much and still bind to human hosts, and hopes the vaccine will “cover the vast majority of strains that are circulating.”

If not, Novavax can continue matching its vaccine to new variants, he said.

Researchers are tracking the variants through data-sharing platforms such as the Global Initiative on Sharing Avian Flu Data, which houses a huge trove of coronavirus genomes.

Scientists recently identified seven U.S. coronavirus variants with mutations all occurring in the same location in a key portion of the virus, offering more evidence of convergent evolution.

Other teams are conducting experiments that expose the virus to antibodies to force it to mutate. In many cases, the same mutations, including the infamous E484K, appeared.

Such evidence adds to cautious optimism that mutations appear to share many of the same traits.

But the world must continue tracking changes in the virus, experts said, and choke off its ability to mutate by reducing transmission through vaccinations and measures that limit its spread.

“It’s shown a very strong set of opening moves,” Vaughn Cooper, an evolutionary biology specialist at the University of Pittsburgh School of Medicine, said of this coronavirus. “We don’t know what the end game is going to look like.”

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)