Vaccination protects people against coronavirus infection much better than previous infection does, a team of researchers led by the U.S. Centers for Disease Control and Prevention reported Friday.
They said their findings should help settle debates over whether people who have been infected should bother getting vaccinated. They should, the researchers said.
People who had not been vaccinated and who ended up in the hospital were five times more likely to have COVID-19 than people who had been vaccinated within the past three to six months, they found.
"All eligible persons should be vaccinated against COVID-19 as soon as possible, including unvaccinated persons previously infected with SARS-CoV-2," the researchers wrote in the CDC's weekly report, the MMWR.
"We now have additional evidence that reaffirms the importance of COVID-19 vaccines, even if you have had prior infection," CDC Director Dr. Rochelle Walensky said in a statement.
"This study adds more to the body of knowledge demonstrating the protection of vaccines against severe disease from COVID-19. The best way to stop COVID-19, including the emergence of variants, is with widespread COVID-19 vaccination and with disease prevention actions such as mask wearing, washing hands often, physical distancing, and staying home when sick."
Researchers across the country collected data on 7,000 people treated at 187 hospitals in nine states for COVID-19-like illnesses between January and September. All were tested for coronavirus. Those who were not vaccinated were 5.49 times as likely to test positive for coronavirus as those who had been vaccinated within the past three to six months -- even if they had a recent COVID-19 infection.
The CDC noted that a Israeli study posted online in August found just the opposite -- but also noted that the Israeli study looked at people who had been vaccinated six month before or longer. "Understanding infection-induced and vaccine-induced immunity over time is important, particularly for future studies to consider," they wrote.
"In this study, the benefit of vaccination compared with infection without vaccination appeared to be higher for recipients of Moderna than Pfizer-BioNTech vaccine, which is consistent with a recent study that found higher vaccine effectiveness against COVID-19 hospitalizations for Moderna vaccine recipients than for Pfizer-BioNTech vaccine recipients," they added.
Israel has attacked Iran, three people familiar with the matter told Reuters, as Iranian state media reported early on Friday that its forces had destroyed drones, days after Iran launched a retaliatory drone strike on Israel.
American millionaire Jonathan Lehrer, one of two men charged in the killings of a Canadian couple in Dominica, has been denied bail.
Nearly half of China's major cities are suffering 'moderate to severe' levels of subsidence, putting millions at risk of flooding especially as sea levels rise.
Prince Harry, the son of King Charles III and fifth in line to the British throne, has formally confirmed he is now a U.S. resident.
The judge presiding over the trial of a man accused of fatally running over a Toronto police officer is telling jurors the possible verdicts they may reach based on the evidence in the case.
Health Canada will change its longstanding policy restricting gay and bisexual men from donating to sperm banks in Canada, CTV News has learned. The federal health agency has adopted a revised directive removing the ban on gay, bisexual and other men who have sex with men, effective May 8.
Colin Jost, who co-anchors Saturday Night Live's 'Weekend Update,' revealed who he thinks is one of the best hosts on the show.
A male columnist has apologized for a cringeworthy moment during former University of Iowa superstar and college basketball's highest scorer Caitlin Clark's first news conference as an Indiana Fever player.
Sophie Kinsella, the best-selling author behind the 'Shopaholic' book series, has revealed that she is receiving treatment for brain cancer.
The judge presiding over the trial of a man accused of fatally running over a Toronto police officer is telling jurors the possible verdicts they may reach based on the evidence in the case.
B.C.'s highest court has dismissed an appeal by an RCMP officer who was found guilty of sex crimes involving teen girls, upholding his conviction.
Saskatchewan Teachers' Federation (STF) President Samantha Becotte says two days of "difficult" negotiations has led to a "final offer" with slight improvements to salary and the inclusion of a line in the collective agreement – promising to address classroom complexity issues.
Nova Scotia's opposition parties are calling for the justice minister to resign after he said domestic violence is not an "epidemic."
Closing arguments were heard Thursday morning in the case of Michael Gordon Jackson, the Saskatchewan man accused of abducting his daughter in 2021 to keep her from getting a COVID-19 vaccine.
Technology from the 19th century has been brought out of retirement at a Newfoundland gardening store, as staff look for all the help they can get to fill orders during a busy season.
Israel has attacked Iran, three people familiar with the matter told Reuters, as Iranian state media reported early on Friday that its forces had destroyed drones, days after Iran launched a retaliatory drone strike on Israel.
Nearly half of China's major cities are suffering 'moderate to severe' levels of subsidence, putting millions at risk of flooding especially as sea levels rise.
San Francisco on Thursday sued Oakland after officials there voted in favor of changing the name of the city’s airport to San Francisco Bay Oakland International Airport, saying the change will cause confusion and is already affecting its airport financially.
A human rights organization representing ethnic Armenians submitted evidence to the ICC, arguing that Azerbaijan is committing an ongoing genocide against them.
An Assyrian church bishop who was stabbed during a service at his church said on Thursday he was recovering quickly, and that he had forgiven his attacker as police ramped up investigation into the riots triggered after the bishop's stabbing.
Kenya's military chief, Francis Ogolla, died in a helicopter crash in the western part of the country on Thursday, President William Ruto announced in a televised address.
Cabinet minister Dominic LeBlanc says he plans to run in the next election as a candidate under Prime Minister Justin Trudeau's leadership, amid questions about his rumoured interest in succeeding his longtime friend for the top job.
Health Canada will change its longstanding policy restricting gay and bisexual men from donating to sperm banks in Canada, CTV News has learned. The federal health agency has adopted a revised directive removing the ban on gay, bisexual and other men who have sex with men, effective May 8.
Most Canadians in March reported feeling angry or pessimistic towards the federal government than at any point in the last six years, according to a survey by Nanos Research.
Bayer announced Thursday it is recalling two lots of its hydraSense Baby Nasal Care Easydose due to a potential contamination.
The U.S. Environmental Protection Agency has finalized stringent new regulations on levels of six perfluoroalkyl and polyfluoroalkyl substances, or PFAS, in public water systems. This explainer tells consumers what they can do right now to limit the levels of PFAS in their drinking water.
The Ottawa Hospital is hoping artificial intelligence will help reduce physician burnout and increase access to care for patients.
An ancient giant snake in India might have been longer than a school bus and weighed a tonne, researchers reported Thursday.
Facebook parent Meta Platforms unveiled a new set of artificial intelligence systems Thursday that are powering what CEO Mark Zuckerberg calls 'the most intelligent AI assistant that you can freely use.'
New archeological investigations in Guatemala reveal that the ancient Maya people had a ritual of burning royal human remains as a public display of political regime change.
Colin Jost, who co-anchors Saturday Night Live's 'Weekend Update,' revealed who he thinks is one of the best hosts on the show.
Halifax actor and activist Elliot Page has been recognized by Time, an American news magazine, as one of the most influential people of 2024.
An attorney has been added to the special prosecution team that is pursuing an involuntary manslaughter charge against actor Alec Baldwin in the fatal shooting of a cinematographer on the set of the Western movie 'Rust,' court officials confirmed Thursday.
Booming sales of cold drinks at Starbucks have created a problem: growing amounts of plastic waste from the single-use cups that Frappuccinos, Refreshers, cold brews and other iced drinks are served in.
Google has fired 28 employees in the aftermath of protests over technology that the internet company is supplying the Israeli government amid the Gaza war, further escalating tensions surrounding a hot-button deal.
Several Tim Horton’s customers are feeling great disappointment after being told by the company that an email stating they won a boat worth nearly $60,000 was sent in error.
Sophie Kinsella, the best-selling author behind the 'Shopaholic' book series, has revealed that she is receiving treatment for brain cancer.
Ten beagles rescued from animal testing in the United States arrived in Alberta on Wednesday, thanks to a Canadian charity.
Molly Knight, a grade four student in Nova Scotia, noticed her school library did not have many books on female athletes, so she started her own book drive in hopes of changing that.
At 6'8" and 350 pounds, there is nothing typical about UBC offensive lineman Giovanni Manu, who was born in Tonga and went to high school in Pitt Meadows.
The NHL Board of Governors voted unanimously Thursday to clear the way for the Coyotes' move to Utah next season.
After knocking out her opponent in the fourth round, Ottawa’s Tayler Kelly is the World Boxing Council (WBC) Muay Thai Canadian amateur champion, a milestone in the fighter's young career.
Tesla will ask shareholders to reinstate a US$55 billion compensation package for CEO Elon Musk that was rejected by a judge in Delaware this year and to move the electric car maker's corporate home from Delaware to Texas.
Tesla has hit a series of roadblocks, including increased competition and declining sales. The company announced Monday it is slashing 10 per cent of its global workforce.
A driver from London will have to find alternative transportation after an OPP officer clocked them travelling nearly 200 km/h on Highway 401 over the weekend.
Kevin the cat has been reunited with his family after enduring a harrowing three-day ordeal while lost at Toronto Pearson International Airport earlier this week.
Molly Knight, a grade four student in Nova Scotia, noticed her school library did not have many books on female athletes, so she started her own book drive in hopes of changing that.
Almost 7,000 bars of pure gold were stolen from Pearson International Airport exactly one year ago during an elaborate heist, but so far only a tiny fraction of that stolen loot has been found.
When Les Robertson was walking home from the gym in North Vancouver's Lower Lonsdale neighbourhood three weeks ago, he did a double take. Standing near a burrow it had dug in a vacant lot near East 1st Street and St. Georges Avenue was a yellow-bellied marmot.
A moulting seal who was relocated after drawing daily crowds of onlookers in Greater Victoria has made a surprise return, after what officials described as an 'astonishing' six-day journey.
Just steps from Parliament Hill is a barber shop that for the last 100 years has catered to everyone from prime ministers to tourists.
A high score on a Foo Fighters pinball machine has Edmonton player Dave Formenti on a high.
A compound used to treat sour gas that's been linked to fertility issues in cattle has been found throughout groundwater in the Prairies, according to a new study.
While many people choose to keep their medical appointments private, four longtime friends decided to undergo vasectomies as a group in B.C.'s Lower Mainland.
The premier of British Columbia is continuing to defend the three-year pilot program underway in his province that’s decriminalized personal possession of hard drugs, even as the federal government sends its minister responsible to discuss growing concerns and controversies.
At 6'8" and 350 pounds, there is nothing typical about UBC offensive lineman Giovanni Manu, who was born in Tonga and went to high school in Pitt Meadows.
Police in Delta are appealing for witnesses and information after a mid-afternoon rollover crash into the front yard of a home last week.
A group of suspects that allegedly defrauded seniors across Ontario and other parts of Canada using a so-called emergency grandparent scam appear to have ties to 'Italian traditional organized crime,' according to an investigator involved in the OPP-led probe.
He was a loving son and brother, a loyal and kind friend, and a dedicated volunteer in Toronto’s east end, say those who knew and loved Mohammad Khasim.
Kevin the cat has been reunited with his family after enduring a harrowing three-day ordeal while lost at Toronto Pearson International Airport earlier this week.
Calgary police say Winston Campbell, 45, has been charged in the death of a two-year-old girl in 2022.
Blake Coleman scored his 30th goal and MacKenzie Weegar got his 20th as the Calgary Flames set multiple personal milestones in a season-ending 5-1 victory over the San Jose Sharks on Thursday night.
Calgary fans of pop superstar Taylor Swift were among the millions of 'Swifties' celebrating the release of 'The Tortured Poets Department', and they were doing it in style.
CTVNewsOttawa.ca looks at things to do in Ottawa this weekend.
The driver killed in a head-on crash on Hwy. 417 in Ottawa's east end was driving eastbound in the westbound lanes when the vehicle collided with a second vehicle, according to Ontario Provincial Police.
The suspect accused of murdering six people at a home in Barrhaven made another brief court appearance Thursday afternoon.
The English Montreal School Board (EMSB) is celebrating what it calls a 'significant win' in court after a judge stayed parts of Quebec's language laws that apply to English school boards across the province.
Quebec intends to follow Ottawa's lead and increase its capital gains tax rate. The Quebec government announced late on Thursday that its tax system will be adjusted to bring it into line with five measures proposed in the latest federal budget.
American millionaire Jonathan Lehrer, one of two men charged in the killings of a Canadian couple in Dominica, has been denied bail.
Alberta is introducing new legislation aimed at preventing spikes in electricity prices.
An Edmonton man is feeling let down after Tim Hortons mistakenly told him he'd won a boat.
Occupational Health and Safety (OHS) is investigating after a worker fell to their death earlier this week.
Nova Scotia Premier Tim Houston says an agreement in principle has been reached on a new contract for public school teachers.
Nova Scotia's opposition parties are calling for the justice minister to resign after he said domestic violence is not an "epidemic."
Some residents in rural New Brunswick are frustrated with cows that roam into their properties.
A Manitoba woman thought she found a miracle natural supplement, but said a hidden ingredient wreaked havoc on her health.
The City of Winnipeg is finally moving ahead with a plan to clear away a large pile of debris on a private lot.
The Mobile Overdose Prevention Site operated by Sunshine House has been in operation since late 2022, and now a report is being released sharing the results of its first year.
On Thursday, Education Minister Jeremy Cockrill apologized for remarks he made to a mother who had advocated for better classroom supports earlier this week.
With the Canadian Dental Care Plan (CDCP) set to roll out on May 1, many dental care providers have concerns and unanswered questions about the plan.
Chris Ross was pleasantly surprised when Tim Hortons sent him an email summarizing his "Roll up the Rim" winnings for the season. The email claimed Ross had won a boat valued at over $50,000 – but it was a mistake.
A property management company in Fergus is still cleaning up after they say a tenant trashed one of their units and refused to pay rent -- and they say it's not the only similar case they've dealt with recently.
Gas prices across Ontario have spiked to levels not seen in nearly two years as the switch from winter fuel to a more expensive summer blend pushes the price at the pumps.
Don’t be alarmed if you see some strange new creatures in Waterloo Park.
Saskatchewan Teachers' Federation (STF) President Samantha Becotte says two days of "difficult" negotiations has led to a "final offer" with slight improvements to salary and the inclusion of a line in the collective agreement – promising to address classroom complexity issues.
The Saskatoon Police Service (SPS) is dedicating three officers to a specialized unit to help curb crime in the Pleasant Hill neighbourhood.
A Saskatchewan village and a contractor it hired are facing significant fines after conservation officers discovered they dumped demolition waste at an illegal landfill.
A private career college in North Bay is under intense scrutiny from students for taking tuition but not offering courses, and from former teachers who say they haven't been paid.
Some communities in northeastern Ontario remain under a state of emergency due to last Friday’s rain.
Tim Hortons says human error is to blame for some customers thinking they had won a boat in a recent digital roll up to win contest.
A Lucan man is facing a number of charges after police said they recovered a stolen truck.
The provincial government is advising there is recourse for those who believe they've been wrongfully billed for healthcare services.
A jury heard some horrific evidence Thursday at the trial of a London, Ont. couple charged with physically and sexually abusing their children.
One person suffered life-threatening injuries after a collision with a commercial vehicle on Highway 12 at Forest Avenue in Orillia early Thursday afternoon.
As inflation tightens its grip on the economy, many people are feeling the pinch, from housing to transportation to retail and services, including restaurants.
The hearing for a Barrie police officer charged with discreditable conduct following an OPP investigation continued Thursday morning over teleconference.
Like many 10 year olds, Brenna Tonon loves to make Rainbow Loom bracelets – but she doesn’t just make them for fun.
Ali Al-Shammari is 20 years into a life sentence for the first-degree murder of Thualfikar Alantiyya, 41, killed on November 19, 2004.
Some Tim Hortons customers in Windsor are feeling dismayed and considering legal action after being told by the company that an email stating they won a boat worth nearly $60,000 was sent in error.
The premier of British Columbia is continuing to defend the three-year pilot program underway in his province that’s decriminalized personal possession of hard drugs, even as the federal government sends its minister responsible to discuss growing concerns and controversies.
A large collection of First Nations art worth more than $60,000 was stolen in Saanich earlier this month, police announced Thursday.
Short-term rental platforms that violate B.C.'s pending regulations can face administrative penalties of up to $10,000 per day, officials announced Thursday.
A banana ball python that was stolen from a Kelowna pet store on Saturday has been returned unharmed, Mounties said.
Nurses held a rally Wednesday at a hospital in the B.C. Interior that closed its emergency department more than a dozen times last year due to insufficient staff.
British Columbia is planning to add 240 new units to its complex-care housing program, providing homes for people with mental-health and addictions challenges that overlap with other serious conditions.
Three men who helped lead and co-ordinate the 2022 border blockade at Coutts, Alta., have been found guilty of public mischief.
Lethbridge police have arrested a Vermilion, Alta., man in connection with a 'grandparent scam' that took aim at a local senior.
An Alberta woman was killed in a multi-vehicle crash on a highway north of Coaldale, Alta., on Wednesday morning.
A 65-year-old northern Ontario woman says her winning lottery scratch ticket is the best present she has ever received.
A northern Ont. city councillor says she fears many women will go without the proper health care after town loses access to mobile cancer screening.
For the next several months, the City of Sault Ste. Marie will be cracking down on people who improperly use accessible parking spaces.
Technology from the 19th century has been brought out of retirement at a Newfoundland gardening store, as staff look for all the help they can get to fill orders during a busy season.
A Celebrity Apex cruise to the Caribbean this month turned into a rocking Newfoundland kitchen party when hundreds of people from Canada's easternmost province happened to be booked on the same ship.
A pricing agreement has been reached between crab fishers and seafood processors that will allow for Newfoundland and Labrador's annual crab fishery to get started.
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