Sugar is not just something we eat. On the contrary. Sugar is one of the most naturally occurring molecules, and all cells in the body are covered by a thick layer of sugar that protects the cells from bacteria and virus attacks. In fact, close to 80 per cent of all viruses and bacteria bind to the sugars on the outside of our cells.
Sugar is such an important element that scientists refer to it as the third building block of life — after DNA and protein. And last autumn, a group of researchers found that the spike protein in corona virus needs a particular sugar to bind to our cells efficiently.
Now the same group of researchers have completed a new study that further digs into the cell receptors to which sugars and thus bacteria and virus bind.
‘We have established how the sugars bind to and activate the so-called Siglec receptors that regulate immunity. These receptors play a major role, as they tell the immune system to decrease or increase activities. This is an important mechanism in connection with autoimmune diseases’, says the first author of the study, Postdoc Christian Büll from the Copenhagen Center for Glycomics (CCG) at the University of Copenhagen.
The unique sugar language
When the immune system receives wrong signals, it can lead to autoimmune diseases, which is when the immune system attacks itself. The Siglec receptors receive signals via the sialic acid sugar, a carbohydrate that typically closes the sugar chains on the surface of our cells. When Siglec receptors meet the right sugar chains, the immune system is told to dampen or activate.
‘As part of the new study, we have created a cell library that can be used to study how various sugars bind to and interact with receptors. We have done this by creating tens of thousands of cells each containing a bit of the unique sugar language, which enables us to distinguish them from one another and to study their individual effect and process. This knowledge can help us develop better treatment options in the future’, says Associate Professor Yoshiki Narimatsu from CCG, who also contributed to the study.
‘The surface of the cells in the library is the same as the one found on cells in their natural environment. This means that we can study the sugars in an environment with the natural occurrence of e.g. proteins and other sugars, and we can thus study the cells in the form in which virus and bacteria find them’, Yoshiki Narimatsu explains.
Important discovery for Alzheimer’s
Working on the new study, the researchers identified the sugars that bind to the specific receptor that plays a main role in the development of Alzheimer’s disease.
‘Our main finding concerns the Siglec-3 receptor. Mutations in the Siglec-3 receptor is already known to play a role in connection with Alzheimer’s, but we did not know what the receptor specifically binds to. Our method has now identified a potential natural sugar that binds specifically to the Siglec-3 receptor. This knowledge represents an important step forwards in understanding the genetic defects that cause a person to develop the disease’, says Christian Büll.
The creation of the sugar libraries was funded by the Lundbeck Foundation and the Danish National Research Foundation.

A new imaging technique developed by scientists at Columbia University Vagelos College of Physicians and Surgeons and St. Jude Children’s Research Hospital captures movies of receptors on the surface of living cells in unprecedented detail and could pave the way to a trove of new drugs.
The researchers used the technique to zoom in on individual receptor proteins on the surface of living cells to determine if the receptors work solo or come together to work as pairs. This work appeared in the April issue of Nature Methods.
“If two different receptors come together to form a dimer with distinctive function and pharmacology, this might allow for a new generation of drugs with greater specificity and reduced side effects,” says Jonathan Javitch, MD, PhD, the Lieber Professor of Experimental Therapeutics in Psychiatry at VP&S.
G-protein coupled receptors (GPCRs) are some of medicine’s most important molecules: About one-third of today’s drugs work by targeting a GPCR. The possibility that GPCRs form heterodimers — consisting of two different flavors of GPCR — is an especially exciting prospect for the development of better drugs.
“The potential of GPCR heterodimers for improved pharmacotherapies, including for disorders such as schizophrenia and depression, is exciting and has drawn us to the field,” Javitch says.
But for decades, scientists have hotly debated whether most GPCRs form dimers or work alone. Much of this impasse stemmed from the relatively poor spatial resolution of current techniques. Different GPCRs in a cell have been captured near each other, but it was unclear if the receptors were working together.
“The controversy over receptor dimerization has only grown fiercer with conflicting data from different labs using different methods,” Javitch says.
Using a new, more powerful technique based on single-molecule fluorescence resonance energy transfer (smFRET), Javitch and Scott C. Blanchard from St. Jude Children’s and Weill Cornell show that dimers can be tracked as they move on the cell surface and how long they last. This method takes advantage of a change in fluorescence that occurs when proteins, labeled with different fluorescent markers, are extremely close to each other. The resolution in this approach is more than 10 times greater than previous techniques.
This new and exciting technique entails multiple innovations in dyes, labeling technology, protein engineering, imaging, and software that enabled tracking of individual and coupled receptors.
Not only does this method detect GPCR dimers, it also allows, for the first time, a clear view of how receptors in a living cell change shape when activated. This will provide researchers a better understanding of how drugs can differentially impact the same receptors.
“With this method, we can now explore receptor interactions and activation mechanisms with unprecedented resolution, giving us an opportunity to investigate new therapeutic approaches,” Javitch says.
Story Source:
Materials provided by Columbia University Irving Medical Center. Note: Content may be edited for style and length.

In their effort to understand the very earliest stages of life and how they can go wrong, scientists are confronted with ethical issues surrounding the use of human embryos. The use of animal embryos is also subject to restrictions rooted in ethical considerations. To overcome these limitations, scientists have been trying to recreate early embryos using stem cells.
One of the challenges in creating these so-called synthetic embryos is to generate all the cell types normally found in a young embryo before it implants into the wall of the uterus. Some of these cells eventually give rise to the placenta. Others become the amniotic sac in which the fetus grows. Both the placenta and the amniotic sac are crucial for the survival of the fetus, and defects in these embryo components are major causes of early pregnancy loss.
A group of scientists from Gladstone Institutes, the Center for iPS Cell Research and Application (CiRA) from Kyoto University, and the RIKEN Center for Biosystems Dynamics Research in Kobe, Japan, has now demonstrated the presence of precursors of the placenta and the amniotic sac in synthetic embryos they created from mouse stem cells.
“Our findings provide strong evidence that our system is a good model for studying the early, pre-implantation stages of embryo development,” says Kiichiro Tomoda, PhD, research investigator at the recently opened iPS Cell Research Center at Gladstone and first author of the study published in the journal Stem Cell Reports. “Using this model, we will be able to dissect the molecular events that take place during these early stages, and the signals that the different embryonic cells send to each other.”
Ultimately, this knowledge might help scientists develop strategies to decrease infertility due to early embryonic development gone awry.
The new findings could also shed light on a defining property of the earliest embryo cells that has been difficult to capture in the lab: their ability to produce all the cell types found in the embryo and, ultimately, the whole body. Scientists refer to this property as “totipotency.”
“Totipotency is a very unique and short-lived property of early embryonic cells,” says Cody Kime, PhD, an investigator at the RIKEN Center for Biosystems Dynamics Research and the study’s senior author.

Isabella died from cancer, aged 11, two years ago. Just after her death, the hospice in Walsall that she’d called her second home faced closure, due to a funding shortfall. But now the £2m required to keep it running has been raised, with a huge community effort bringing in public donations amounting to more than half the sum.Isabella’s parents, Mark Lyttle and Jennie Day, spoke to BBC Breakfast.

SharecloseShare pageCopy linkAbout sharingimage copyrightGetty ImagesA malaria vaccine has proved to be 77% effective in early trials and could be a major breakthrough against the disease, say its developers from the University of Oxford.Malaria kills more than 400,000 people a year, mostly children in sub-Saharan Africa.But despite many vaccines being trialled over the years, none has met the required target for success.The researchers say the vaccine could have a major public health impact.When trialled in 450 children in Burkina Faso, the vaccine was found to be safe, and showed “high-level efficacy” over 12 months of follow-up.Larger trials in nearly 5,000 children between the ages of five months and three years will now be carried out across four African countries, to confirm the findings. Malaria is a life-threatening disease caused by parasites that are transmitted to people through mosquito bites. Although preventable and curable, the World Health Organization estimates there were 229 million cases worldwide in 2019 and 409,000 deaths.The illness starts with symptoms such as fever, headaches and chills and, without treatment, `can progress quickly to severe illness and often death.’Major health impact’Adrian Hill, director of the Jenner Institute and professor of vaccinology at the University of Oxford, and co-author of the paper, said he believed the vaccine was the first to reach the World Health Organization’s goal of at least 75% efficacy.The most effective malaria vaccine to date had only shown 55% efficacy in trials on African children.The trials of this malaria vaccine started in 2019, long before coronavirus appeared – and the Oxford team developed its Covid vaccine on the strength of its research into malaria, Prof Hill said.He said a malaria vaccine had taken much longer to come to fruition because there are thousands of genes in malaria compared to around a dozen in coronavirus, and a very high immune response is needed to fight off the disease.”That’s a real technical challenge,” he said. “The vast majority of vaccines haven’t worked because it’s very difficult.”However, Prof Hill said the trial results mean the vaccine “has the potential to have a major public health impact”.’Tool for saving lives’In a pre-print study with The Lancet, the research team – from Oxford, Nanoro in Burkina Faso and the US – reported the trial results of R21/Matrix-M, which tested a low and high dose of the vaccine between May and August, before peak malaria season.The vaccine showed 77% efficacy in the higher-dose group and 71% in the lower-dose group.Halidou Tinto, professor in parasitology and the principal trial investigator at the Clinical Research Unit of Nanoro, Burkina Faso, said the results were “very exciting” and showed “unprecedented efficacy levels”.”We look forward to the upcoming ‘phase III’ trial to demonstrate large-scale safety and efficacy data for a vaccine that is greatly needed in this region.”The Serum Institute of India, which has manufactured the vaccine, says it is confident of delivering more than 200 million doses of the vaccine as soon as it is approved by regulators.Novavax provided the adjuvant for the vaccine.Malaria is one of the leading causes of childhood mortality in Africa and Prof Charlemagne Ouédraogo, minister of health in Burkina Faso, said the new data showed that a new malaria vaccine could be licensed “in the coming years”. “That would be an extremely important new tool for controlling malaria and saving many lives.”Related Internet LinksMalariaThe BBC is not responsible for the content of external sites.

The Centers for Disease Control and Prevention’s independent vaccine advisory panel is meeting today to review the latest findings about a potential rare side effect that led to a pause in the use of the Johnson & Johnson Covid-19 vaccine.If the panel, the Advisory Committee on Immunization Practices, decides that the vaccine’s benefits outweigh the potential risk, then the government is likely to end the pause.The meeting comes 10 days after the U.S. government recommended that inoculations with the Johnson & Johnson Covid-19 vaccine be halted while researchers investigated six reports of unusual blood clots out of 6.8 million people who had received it.Top officials said in interviews with The New York Times that they had found a few additional cases of the rare blood clots, but would not specify how many. They said that the overall rate did not appear to have changed significantly since last week.The committee could recommend that Johnson & Johnson add a formal warning label about the side effect, as the company has done in the European Union. Roughly 10 million doses or more of the vaccine, produced at the company’s factory in the Netherlands, are sitting on shelves across the United States and could be deployed immediately.The meeting comes as the federal government is also investigating problems at a Baltimore factory that was slated to help satisfy the country’s demand. Emergent BioSolutions, the plant’s operator, has produced tens of millions of doses of Johnson & Johnson’s vaccine, but they cannot be distributed until regulators certify the plant.After Emergent had to discard up to 15 million possibly contaminated doses of the vaccine last month, federal regulators conducted an inspection that found a series of problems, including the risk that other batches could have been contaminated.Last week’s pause followed reports of six women who experienced a rare type of blood clot in the brain within three weeks of getting the Johnson & Johnson vaccine. The clots were accompanied by an unusual drop in platelets, components of the blood that normally help heal wounds.On Thursday, the Oregon health authorities reported that a death was being investigated for a possible connection to the Johnson & Johnson vaccine. The woman who died was in her 50s and had symptoms consistent with the blood clotting cases identified in eight other Johnson & Johnson recipients in the U.S. Dr. Shimi Sharief, the state health authority’s senior health adviser, emphasized that it was not known whether the woman’s death was related to the vaccine.The C.D.C. committee met the day after the announcement, and a representative from Johnson & Johnson provided details on the six cases, along with two others. Rather than voting, the panel decided to hold a second meeting the following week, giving them time to better assess the data.European regulators, who have also been scrutinizing the shots, said on Tuesday that they would allow these vaccinations to resume with the addition of a formal warning label.

Without hospitals or medical specialists in space, NASA and other space agencies have always been concerned about astronauts falling sick during a mission. To minimize the chances of that, they typically spend the two weeks before launch in quarantine.A Covid-19 superspreader event at the space station would disrupt operations.The interior of the space station has a volume equivalent to a Boeing 747 jetliner, so there would be space for infected crew members to isolate themselves. But space station managers certainly would not want to worry about the virus spreading in the station’s perpetually filtered and recycled air.During a news conference last week, Shane Kimbrough, the NASA astronaut who is the commander of Crew-2, said all four astronauts had received Covid vaccinations. “I guess it went fine,” he said. “We all have a little bit different reactions, just like most people do. So we’re no different in that regard. But we’re thankful that we have the vaccines.”The three astronauts who launched in a Soyuz rocket to the station earlier this month — Oleg Novitskiy and Pyotr Dubrov of the Russian space agency and Mark Vande Hei of NASA — were also vaccinated.The four astronauts of the Crew-1 mission are not, because no vaccines were available when they launched last November. When they return to Earth, every human not on the planet will be vaccinated against Covid-19.

Railings, grab bars, shower chairs and other inexpensive devices can make it easier to continue living at home, but not enough older people acquire them.In 2019, John Hancock had become so disabled after a hospitalization that he went close to a year without being able to take a bath or a shower. Using a walker, he could, with difficulty, move around the townhouse in Baltimore where he lived with his daughter and grandson. But because he felt too unsteady to climb into the tub, one of them had to help him with sponge baths.Then a program at Johns Hopkins called CAPABLE (Community Aging in Place — Advancing Better Living for Elders) sent a nurse, an occupational therapist and a repair person to provide some inexpensive assistive devices. “It made a tremendous difference in my life,” Mr. Hancock, a retired school cook, said.Over several visits, the team asked about his needs and priorities and supplied a shower chair and a rubber bath mat. The repair person installed grab bars around the tub, attached a hand-held shower nozzle and added a railing next to the toilet. Mr. Hancock learned how to use it all.“I feel safe and I feel secure,” he said recently. “I don’t have to call somebody to help me. I feel independent, and I’ve been independent all my life.” Recovering well from a recent stroke, Mr. Hancock, now 64, can not only bathe on his own but can also cook for himself, manage stairs and go to church.How many older adults could benefit from such simple, low-cost, nonprescription devices? And how many actually acquire them?A team at the University of California, San Francisco, combed through national data and came up with an estimate, recently published in JAMA Internal Medicine: About 12 million people over 65, living in their own homes, could use equipment to help them safely bathe and use the toilet, two of the activities disabled older people most commonly struggle with. But about five million of them don’t have those items, even though they generally cost less than $50.Looking at Medicare beneficiaries in the National Health and Aging Trends Study in 2015, the researchers identified more than 2,600 people (average age: about 80) who needed such devices, based on measures like holding onto walls as they walked and being unable to rise unassisted from a chair.“They’re not as nimble as they used to be,” said Dr. Kenneth Lam, a geriatrician and lead author of the study. “They’re the parents you’re starting to worry about.”Mr. Hancock demonstrates the grab bars and shower chair CAPABLE put in his bathroom. “It was amazing,” he said. “I was overwhelmed and full of joy. I haven’t gone to the shower in a year.”Rosem Morton for The New York TimesOf those who could have benefited from a shower chair and grab bars for bathing, 26 percent did not have either and only 40 percent had both. In the group who could have used a raised toilet or toilet seat, plus a grab bar for toilet use, 44 percent had neither and 24 percent had both. Extrapolating to the national population produced the five million estimate.“It’s a technical problem which, unlike so much of aging, is actually solvable,” Dr. Lam said. Yet after four years, the researchers found, many participants in need still had not acquired the equipment, or had died without it.“In the hospital, I can order an M.R.I. and charge the system thousands of dollars,” Dr. Lam said. “But down the road, that won’t help patients not fall. What happens when they get home?”Home is where older adults want to stay. Covid-19 and its predations and restrictions have made senior living facilities increasingly unpopular; occupancy rates in the first quarter of this year reached a record low, the National Investment Center for Seniors Housing and Care has reported.Yet, “there are people all over the country whose homes don’t fit what they need,” said Sarah Szanton, a nursing researcher at Johns Hopkins University and director of the decade-old CAPABLE program in Baltimore. Thirty-three similar programs now operate in 18 states.What doctors and therapists (and families) worry about most in such cases are falls, a leading cause of hospitalization and disability for older people. Bathrooms, with their hard and slippery surfaces, pose a particular danger.CAPABLE, deploying its multi-specialty team and a modest budget of $1,300 per household for repairs, equipment and installation, offers low-income residents not only bathroom equipment but also kitchen grabbers, well-anchored banisters and other useful articles.And it pays off. “On average, people’s disability is cut in half,” Dr. Szanton said. “Their pain decreases. Their ability to bathe and dress improves. People stuck on the second floor of their houses for years can go on family trips.”CAPABLE reduced Medicaid spending and could create Medicare savings as well. Participants reported that it helped them remain at home, made their homes safer and helped them care for themselves.Elsewhere, users of assistive devices tell similar stories. “We all know someone who had an aunt or a mother who couldn’t get out of the tub or off the floor, and bad things happened,” said Wendl Kornfeld, 72, who lives in Manhattan with her 83-year-old husband.They had grab bars installed in their two showers for roughly $120 total, “not a huge investment and worth it for peace of mind,” Ms. Kornfeld said.In Mt. Kisco, N.Y., Joan Potter appreciates the apartment renovations her late husband oversaw 20 years ago. He used a wheelchair, so their bathroom had a roll-in shower with a hand-held shower head, a raised toilet and grab bars in key locations. Now that Ms. Potter, 88, has undergone two hip replacements, she said, “I’m so grateful I have all these things, because I’m not so agile myself anymore.”Why don’t more seniors take advantage of such devices?Some adaptations that help people remain at home, like outdoor ramps and stair glides, carry high price tags; basic bathroom devices, widely available in pharmacies and online, generally don’t. But cost can still present an obstacle.“Medicare covers ‘durable medical equipment’ — hospital beds, wheelchairs, walkers,” said Tricia Neuman, who leads the Kaiser Family Foundation’s program on Medicare. “It doesn’t cover hand rails or grab bars, things used around the house.”With the help of new railings, Mr. Hancock can manage stairs again.Rosem Morton for The New York TimesMedicare Advantage plans have more flexibility, but a Kaiser study found that of Advantage enrollees, only six percent were in plans that covered bathroom safety equipment.A recently announced federal program from the Department of Housing and Urban Development will provide $30 million for a home modification program for low-income homeowners aged 62 and older, a helpful but small step.Moreover, price isn’t the only barrier to assistive equipment. “You need whole systems to deliver it,” Dr. Lam said. Sometimes, faced with the challenges of selecting the appropriate devices, ordering and installing them, “even for people who want them, it just doesn’t happen.”And a lot of seniors don’t want them. “These are symbols to people that they’re losing control,” said Marcie Gleason, a social psychologist at the University of Texas at Austin who studies such issues. “It feels like dependency to need these devices — even though they probably help them remain independent.”Karen Purze spent a decade caring for her late parents, who hoped to age in place in their Chicago home. She worried every time her father, undergoing cancer treatment in his late 70s, climbed in and out of an old-fashioned claw-foot bathtub without supports.She suggested modifications, but “he wouldn’t listen.” He’d say, “‘I don’t need that. I’m fine,’” Ms. Purze recalled. “He was clinging tightly to every bit of independence.”Trying to overcome that resistance, and simplifying the process of acquiring and using safety equipment, will require a multipronged effort, with more attention from primary care doctors, more programs like CAPABLE and shifts in Medicare policies.But it may require changes in outlook, too. Ms. Purze, 50, and her husband are most likely years away from needing raised toilets and shower chairs — but are already talking about them.In their next house? “Grab bars, for sure,” she said. “I’ve seen how important it is, in maintaining your independence, that your house helps you and doesn’t hinder you.”

Cruise companies and their allies are fighting against rules that have kept U.S. ships from sailing. But experts say controlling the coronavirus onboard is a complex puzzle.In the United States, flights are filling up, hotels are getting booked, vacation rentals are selling out and car rental companies are facing a shortage because of spiking demand.But one sector remains stalled: the cruise industry.Cruise ships sailing out of United States ports have been docked for more than a year following a series of outbreaks of the coronavirus onboard vessels at the start of the pandemic. Now, cruise companies can restart operations only by following rules laid out by the Centers for Disease Control and Prevention in October.Earlier this month, the C.D.C. published a set of technical guidelines to help cruise companies prepare their ships to start sailing again in line with those rules, which were set out in the agency’s Framework for Conditional Sailing Order. But the Cruise Lines International Association (CLIA), the industry’s trade group, called the instructions “so burdensome and ambiguous that no clear path forward or timetable can be discerned.”Cruise companies have asked the agency to revise its guidelines to factor in the speedy rollout of vaccinations and allow for U.S. sailings to restart in July. But the C.D.C. has not yet provided a firm date, and under the current rules, cruise ships must follow a monthslong process that includes simulation voyages to test out their health and safety protocols, followed by a review period.“The cruise industry as a whole is very frustrated,” said Stewart Chiron, a cruise industry analyst and chief executive of the news site cruiseguy.com. “Travel is resuming at a very high level. Airplanes and hotels are packed, and no industry is better suited to restart than cruising. The lines are prepared, safety protocols are in place and now, with the high level of vaccine distribution, they feel it’s a good time to resume operations.”In response to the C.D.C.’s delay of U.S. sailings, some cruise lines are moving their ships abroad to launch summer cruises from foreign ports, including from the Caribbean and Europe, where they are permitted to sail. Many of the voyages require adult passengers and crew members to be vaccinated.Christine Duffy, the president of Carnival Cruise Line (center), at a groundbreaking in January for the company’s new cruise terminal at PortMiami. Lynne Sladky/Associated PressCarnival, the world’s largest cruise company, has warned that it might also look outside the United States if the C.D.C. continues to prevent cruises from sailing domestically.CLIA paints the C.D.C. as targeting the industry unfairly, and points to the global economic impact of the initial suspension of cruise operations from mid-March to September of last year, the latest period for which it has statistics. The group says there was a loss of $50 billion in economic activity, 334,000 jobs and $15 billion in wages.But health experts note the number and severity of outbreaks on ships last year when, for example, more than 700 people became infected with the virus on the Diamond Princess cruise ship in Japan and 14 people died. “The C.D.C. wants to prevent people from getting sick and the cruise lines want to go back to business and start making money,” said Tara Kirk Sell, an assistant professor at the Johns Hopkins Center for Health Security. “So there’s going to be a central disconnect and tension there as we sort our way through this pandemic, which isn’t over yet, and we are still trying to figure out.”Gov. Ron DeSantis of Florida, at a news conference announcing that the state was suing the C.D.C. over its rules for cruise ships. Wilfredo Lee/Associated PressFlorida joins the fightThe state of Florida is home to PortMiami, the world’s busiest cruise port, and it probably has the most to lose if cruise companies shift more sailings to the nearby Caribbean.Earlier this month, Senators Rick Scott and Marco Rubio of Florida (both Republicans), along with Senator Dan Sullivan of Alaska (also Republican), introduced the Cruise Act bill that, if passed, would revoke the agency’s Conditional Sail Order and require it to issue new guidance to restart United States sailings. (Because of a quirk of maritime law, several major cruise lines have canceled all 2021 sailings to Alaska.)“With the way this is going, it seems that the C.D.C. doesn’t want the cruise industry to be in business because they are not setting the rules in a manner that the cruise industry feels they can comply and safely return to work,” Senator Scott said in a telephone interview.“Cruise lines clearly want their passengers and employees to be safe,” he continued. “They have been working all year to prepare their ships, but the C.D.C. has been very difficult to work with and if they don’t want to help then we’ll make sure they do it because we are going to pass this legislation.”The state of Florida has sued the federal government to demand cruise ships be allowed to start sailing immediately.Gov. Ron DeSantis, also a Republican, has maintained that the cruise ban has had a disproportionate impact on the state’s economy; cruises usually generates billions of dollars from the millions of passengers that pass through Florida’s ports each year.“People are going to cruise one way or another. The question is are we going to do it out of Florida, which is the number one place to do it in the world, or are they going to be doing it out of the Bahamas or other locations?” Gov. DeSantis said, speaking at a recent news conference at PortMiami.Ms. Sell said she thinks the C.D.C.’s phased approach, where safety protocols are tested out before passengers are allowed back on onboard, is the right one.“Cruises have for a long time had a potential to super spread diseases that include Covid because people are often in close quarters,” she said. “I’m not saying that you could never do cruises again, but that it just needs to be something where you sort through all the requirements.”Battle over vaccinationsMs. Sell, and other health experts say that requiring everyone onboard to be vaccinated against the coronavirus is one of the best ways to prevent outbreaks. Several cruise lines have made vaccinations a requirement for smaller U.S. river cruises and foreign sailings.But while Gov. DeSantis is arguing for cruises to restart, he has also issued an executive order banning Florida businesses from requiring proof of vaccination from people seeking to use their services. The governor’s office said that the order prohibits all cruise lines from requiring vaccine certificates for their Florida operations.The C.D.C. recommended vaccinations in its latest technical guidance, but stopped short of making them a requirement, avoiding a conflict with Florida.Requiring vaccinations appeals to at least some would-be cruisers. “I’m really excited to get back on a cruise, but I don’t think I could fully relax and enjoy it if everyone on board wasn’t vaccinated,” said Molly Osborne, an avid cruiser based in South Florida. “It would be a great shame if we had to travel to other U.S. ports to get on a ship. Florida is the cruising capital of the world.”Still, Ms. Osborne said she is open to traveling abroad to get on a cruise if the C.D.C. doesn’t lift its ban by the fall. “I haven’t booked anything yet as I’m waiting to see what happens, but if the only way to go this year is from the Caribbean, then I’ll probably do it.”Passengers enjoy the sun on board the MSC Grandiosa in Italian waters. Companies in Europe and other places have restarted sailings. Andrew Medichini/Associated PressWhite House meetingExperts from the C.D.C. and White House staff met with cruise line executives and industry leaders last week to discuss the details of the Conditional Sailing Order.“The objective of the meetings are to mutually review the top priority issues of the cruise industry to work out implementation details of the CSO, including the impact of vaccines and other scientific developments since the CSO was issued in October 2020,” the agency said in a statement. “This goal aligns with the desire for the resumption of passenger operations in the United States by midsummer, expressed by many major cruise ship operators and travelers.”In the meantime, cruise lines are focusing on launching summer sailings abroad in Europe, Asia and the Caribbean. MSC Cruises, the industry’s fourth-largest operator, announced on Thursday that it would be canceling all U.S. cruises through June 30 and instead plans to have at least 10 ships sailing out of Europe and the Mediterranean by August. Royal Caribbean, the second-largest by passenger count, is sailing out of the Bahamas and Bermuda, among other places, and is requiring vaccinations for all crew and passengers.Before vaccines were being widely distributed, cruises lines operating in Europe reported some Covid infections on board, but say that the cases were brought under control using stringent health and safety protocols, which prevented any larger outbreaks.The C.D.C.’s advisory regarding cruise travel remains at a Level 4, the highest, and the agency recommends that all people avoid travel on cruise ships, including river cruises, worldwide.“That’s because the chance of getting Covid-19 on cruise ships is high since the virus appears to spread more easily between people in close quarters aboard ships,” the warning says.Follow New York Times Travel on Instagram, Twitter and Facebook. And sign up for our weekly Travel Dispatch newsletter to receive expert tips on traveling smarter and inspiration for your next vacation. Dreaming up a future getaway or just armchair traveling? Check out our 52 Places list for 2021.

SharecloseShare pageCopy linkAbout sharingimage copyrightGetty ImagesThe chances of becoming infected by Covid fell sharply after a first dose of either the AstraZeneca or Pfizer vaccines, a UK study has found.The vaccines worked just as well in the over-75s and those with underlying health conditions, as other people.The Office for National Statistics (ONS) and University of Oxford research also found a strong antibody response in all age groups from either jab.Everyone showed some response to both vaccines, they said.The research, contained in two studies which have not yet been peer-reviewed or published, is based on virus tests from 370,000 people in the general UK population – one of the largest to date.It provides further real-world evidence that the vaccines being used in the UK to protect against Covid-19 are effective at protecting people against coronavirus infections.In the first study, people who had been vaccinated with a single dose of either the Oxford-AstraZeneca or Pfizer-BioNTech vaccines were 65% less likely to get a new Covid infection.Variant protectionThree weeks after their jab, given between December 2020 and early April 2021, infections with symptoms fell by 74%, while infections with no reported symptoms fell by 57%.Those who had received a second vaccine dose of Pfizer were 90% less likely to be infected. The same calculation could not be made for AZ, because too few people in the study had received a second dose as its rollout started later.The study showed both vaccines were effective against the Kent variant (B117) which was circulating at the time. Dr Koen Pouwels, senior researcher in University of Oxford’s Nuffield Department of Population Health, said the data backed up the decision to extend the gap between doses.”The protection from new infections gained from a single dose supports the decision to extend the time between first and second doses to 12 weeks to maximise initial vaccination coverage, and reduce hospitalisations and deaths,” he said.However, he said the figures showed there was still a chance vaccinated people could acquire Covid again and pass it to others, emphasising the need for social distancing and masks.Past infection boosts Covid jab response six-foldVaccines slow coronavirus spread, study suggests’Encouraging’ antibody boost after both Covid jabsThe second study, in nearly 46,000 adults who had been vaccinated with one dose, found strong antibody responses – a sign that the vaccines are stimulating the body’s defence system to protect against the virus – in all age groups.These antibody responses were “broadly sustained out to 10 weeks afterwards”, the researchers said.Although antibody levels rose more slowly and to a lower level with a single dose of Oxford-AstraZeneca, they dropped more quickly after one Pfizer dose, particularly in older age groups.Antibody boost for over-80sThere was a better response in younger adults compared with older adults over 60 with both jabs, but after two doses of Pfizer antibody levels were high across all ages, the study said.One finding that surprised researchers was the amount by which the immune response shot up in the over-80s after a second dose – far more than in younger age groups.The findings highlight the importance of people getting their second vaccine dose for increased protection, the researchers said.But it is still not clear what the build-up of antibodies after a Covid vaccine actually means.Prof Sarah Walker, chief investigator on the studies, from the University of Oxford, said: “We don’t yet know exactly how much of an antibody response, and for how long, is needed to protect people against getting Covid-19 in the long term – but over the next year, information from the survey should help us to answer these questions.”Both studies are based on data from the Covid-19 Infection Survey, a partnership between the University of Oxford, the ONS and the Department for Health and Social Care.