A salmonella outbreak that was linked to Gold Medal flour is over, the U.S. Centers for Disease Control and Prevention said Wednesday. However, consumers should still make sure they don't have any recalled bags of flour at home.In late April, General Mills recalled certain 2-, 5- and 10-pound bags of Gold Medal Bleached and Unbleached All-Purpose Flour with use-by dates of March 27 and 28, 2024. The CDC says data showed that some Gold Medal flour was contaminated with Salmonella infantis bacteria that was responsible for at least 14 infections in 13 states. Nearly all of the patients interviewed reported eating raw dough or batter, and all of those who recalled the flour brand identified Gold Medal.A U.S. Food and Drug Administration investigation identified a single production facility for the flour that the sick people used, and an inspection of the General Mills facility in Kansas City, Missouri, turned up a sample with the outbreak strain of the bacteria."Although this outbreak investigation has ended, CDC advises you to throw away or return any bags of recalled flour and to wash any containers used to store recalled flour with warm water and soap," the CDC says.Salmonella infection typically causes diarrhea, fever and stomach cramps six hours to six days after consuming the bacteria. Most people recover without treatment in four to seven days, and because they aren't tested for salmonella, the true number of infections in the outbreak is most likely higher than what was reported, the CDC says. Some people – kids under 5, adults over 65 and those with weakened immune systems – may have more severe illness that requires medical treatment or hospitalization.Most flour is raw and hasn't been treated to kill germs that cause food poisoning, according to the CDC. Salmonella bacteria dies when it is cooked or baked, but people can get sick when eating or tasting foods that include raw flour. Raw dough used for crafts and play clay also pose a risk.The CDC advises baking or cooking any foods made with any brand of raw flour before eating. Thoroughly wash hands, bowls, utensils and surfaces after using raw flour. If making play dough at home, use heat-treated flour.

Researchers are on the cusp of rolling out a new vaccine to combat the respiratory syncytial virus amid an increase in cases in recent months.RSV has become the second leading cause of hospitalization, and tens of thousands of people a year die from it. Children under 2 and adults older than 60 are most at risk for serious disease, and a vaccine has been elusive -- until now."It will be a huge, huge breakthrough for us to have an RSV vaccine available," said Dr. James Campbell, professor of pediatrics and the University of Maryland School of Medicine.RELATED: Sinai pediatrician describes ICU availability amid increase in RSV casesModerna released preliminary results of their vaccine for RSV that shows it's more than 80% effective at preventing serious disease in people older than 60. The company is preparing to submit the vaccine to the Food and Drug Administration for approval, which follows submissions from Pfizer and GlaxoSmithKline late last year."The Pfizer vaccine, they also relayed results on giving that same vaccine to pregnant women, and then what happens is the antibodies the woman makes, gets passed through the placenta into the baby, and they showed very good protection in the first three months of life," Campbell said.Clinical trials are underway on a vaccine for babies and young children, who are among the high-risk groups for developing complications and dying from RSV.RELATED: Maryland hospitals concerned over surge of children with RSVThese would be the first RSV vaccines approved, which would be a feat because researchers have been working on them since the 1960s. Moderna's version uses the mRNA technology made famous by its COVID-19 vaccine."The reason why they could move so quickly on the COVID vaccine was because they had already been studying this RSV vaccine that we're just learning about now, and they used that same technology, and a lot of the tricks they found from that, in order to develop the COVID vaccine," Campbell said.RSV video playlist below:Campbell cautioned the results in the RSV vaccine study are preliminary and are not yet peer-reviewed, so while promising, he's waiting for the full details."That doesn't take away that this is really exciting news, but I think everyone should be waiting to see what the final, all the data show for this vaccine and the other RSV vaccines," Campbell said.Campbell said researchers are hopeful that some of these vaccines will be approved in time for RSV season in the fall.LINK: Maryland Department of Health website for RSV

The U.S. Centers for Disease Control and Prevention is urging health care providers and consumers to stop using EzriCare Artificial Tears as it conducts an investigation into at least 55 infections in 12 states that have led to instances of permanent vision loss, hospitalization and one death.Most people with infections reported using at least one of more than 10 brands of artificial tears, and the majority of these patients reported using EzriCare's product, the agency says. These eye drops are preservative-free, meaning they don't have ingredients to prevent bacterial growth.The CDC says it received reports of infections of the cornea, intraocular fluids, respiratory tract and urinary tract, as well as sepsis.Testing of open EzriCare bottles identified Pseudomonas aeruginosa bacteria that are resistant to a broad array of antibiotics: cefepime, ceftazidime, piperacillin-tazobactam, aztreonam, carbapenems, ceftazidime-avibactam, ceftolozane-tazobactam, fluoroquinolones, polymyxins, amikacin, gentamicin and tobramycin. However, bacterial isolates that were tested against cefiderocol were susceptible to it.The bacteria in the open bottles could have come from contamination either during use or during the manufacturing process, the CDC says. Testing of unopened bottles is ongoing.New Jersey-based EzriCare says in a statement that after learning about the investigation Jan. 20, it "immediately took action to stop any further distribution or sale of EzriCare Artificial Tears. To the greatest extent possible, we have been contacting customers to advise them against continued use of the product."The eye drops are made in India, and "we understand that the same product is also marketed under other brand names," the company says. The manufacturer, Global Pharma Healthcare PVT Limited, is working with the U.S. Food and Drug Administration on a recall, EzriCare says.The CDC urges health care providers to immediately stop using EzriCare Artificial Tears. They should advise their patients who use this product to watch for signs of infection and ask about product use in patients who have eye infections.The CDC also advises consumers to stop using these EzriCare eye drops and to ask for alternative products if their health care provider recommended EzriCare.Pseudomonas bacteria are common in the environment, such as in soil and water. Pseudomonas aeruginosa is usually spread in health care settings, the CDC says, and is increasingly difficult to treat because of antibiotic resistance. It caused more than 32,000 infections in hospitalized patients and about 2,700 deaths in the U.S. in 2017.

U.S. poultry producers are increasing safety measures with flocks as the Centers for Disease Control and Prevention monitor a "highly pathogenic" strain of bird flu which has already been detected in a turkey flock in Indiana, the U.S. Department of Agriculture warned on Wednesday.

As Reuters reported, disease experts are warning the public that wild birds are likely the cause of the bird flu spread which is said to be a highly lethal form of avian flu spreading across the country.

On Feb. 9 the CDC released a statement that said while the health agency believes the risk to the public is low, the statement said, "Outbreaks in domestic poultry, in addition to infections in wild birds, may result in increased exposures in some groups of people, particularly poultry workers, for example."

The USDA said in a statement, "Avian influenza does not present an immediate public health concern. No human cases of these avian influenza viruses have been detected in the United States. As a reminder, the proper handling and cooking of poultry and eggs to an internal temperature of 165 ˚F kills bacteria and viruses."

On Monday Feb. 7, an Indiana farmer discovered around 100 dead turkeys on his farm and saw surviving turkeys appearing to be sick, according to the Indy Star, which reported that almost 30,000 turkeys had to be killed to contain the spread of the virus.

NEW YORK —

The Centers for Disease Control and Prevention on Tuesday explained the scientific rationale for shortening its COVID-19 isolation and quarantine recommendations, and clarified that the guidance applies to kids as well as adults.

The CDC also maintained that, for people who catch COVID-19, testing is not required to emerge from five days of isolation — despite hints from other federal officials that the agency was reconsidering that.

The agency announced the changes last week, halving the isolation time for Americans who catch the coronavirus and have no symptoms or only brief illnesses. Isolation should only end if a person has been fever-free for at least 24 hours without the use of fever-reducing medications and if other symptoms are resolving, the CDC added.

It similarly shortened the time that close contacts need to quarantine, from 10 days to five.

CDC officials previously said the changes were in keeping with evidence that people with the coronavirus are most infectious in the two days before and three days after symptoms develop.

Some experts have questioned how the new recommendations were crafted and why they were changed amid a spike in cases driven largely by the highly contagious omicron variant. Some also expressed dismay that the guidelines allowed people to leave isolation without getting tested to see if they were still infectious.

On Tuesday, the CDC posted documents designed to address those — and other — questions about the latest recommendations. The new guidance applies to school children as well as adults, the CDC said, responding to questions raised by school leaders around the country.

In laying out the scientific basis for the revisions, the agency said more than 100 studies from 17 countries indicate that most transmission happens early in an infection. The CDC acknowledged the data come from research done when delta and other pre-omicron variants were causing the most infections. But the agency also pointed to limited, early data from the U.S. and South Korea that suggests the time between exposure and the appearance of symptoms may be shorter for omicron than for earlier variants.

The CDC also took up the question of why it didn't call for a negative test before people emerge from isolation.

On Sunday, Dr. Anthony Fauci — the White House's top medical adviser — said the CDC was considering including the negative test as part of its guidance.

The agency said lab tests can show positive results long after someone stops being contagious, and that a negative at-home test may not necessarily indicate there is no threat. That's why, the agency said, it was recommending that people wears masks everywhere for the five days after isolation ends.

It did offer tips for those who have access to the tests and want to check themselves before leaving isolation.

Dr. Eric Topol, the head of the Scripps Research Translational Institute, accused the agency of furthering confusion. He agreed that it is appropriate to shorten isolation time, but only with testing.

"We do need to come up with a strategy that limits isolation time, but we don't want it to be one that's adding to the spread of the virus and unwittingly leading to the virus circulating," he said.

Yale University's Dr. Howard Forman said the updated recommendations were communicated poorly last week, but he also applauded the CDC for trying to be more nimble while dealing with limited science, a short supply of tests and an intensifying wave of infections.

Under the previous isolation and quarantine recommendations, "it was obvious that ... society was literally going to be disrupted. If you expected people to comply with those (old) rules, you might as well have a lockdown," said Forman, a radiologist who teaches public health policy.

The agency acknowledged people weren't following the longer recommendations: Research suggests only 25% to 30% of people were isolating for a full 10 days under the older guidance, the CDC said.

The CDC also suggests that people exposed to the virus quarantine for five days, unless they have gotten booster shots or recently received their initial vaccine doses. The agency said anyone exposed — regardless of vaccination status — should get tested five days later, if possible.

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Associated Press writer Carla K. Johnson contributed to this report.

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The Associated Press Health & Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content.

People with certain health conditions that make them moderately or severely immunocompromised may get a fourth mRNA COVID-19 shot, according to updated guidelines from the U.S. Centers for Disease Control and Prevention.The CDC authorized a third dose or certain immunocompromised people 18 and older in August. It said a third dose, rather than a booster — the CDC makes a distinction between the two — was necessary because the immunocompromised may not have had a complete immune response from the first two doses.A study from Johns Hopkins University this summer showed that vaccinated immunocompromised people were 485 times more likely to end up in the hospital or die from COVID-19 compared to most vaccinated people. In small studies, the CDC said, fully vaccinated immunocompromised people accounted for about 44% of the breakthrough cases that required hospitalization. People who are immunocompromised are also more likely to transmit the virus to people who had close contact with them.The U.S. Food and Drug Administration has also authorized booster shots of all three available vaccines for certain people and that would include the immune compromised, the CDC says.Research showed that a booster dose enhanced the antibody response to the vaccine in certain immunocompromised people.That would make for a fourth shot at least six months after completing the third mRNA vaccine dose. At this time, the CDC does not have a recommendation about the fourth shot. People should talk to their doctors to determine if it is necessary, the CDC says.Moderately to severely immunocompromised people include those who are in active cancer treatment for cancers of the blood or for tumors, certain organ transplant and stem cell recipients, people with advanced or untreated HIV, and those who take a high-dose corticosteroids or other drugs that may suppress their immune systems. The CDC estimates about 9 million people who live in the U.S., or about 2% of the population, fall into this category.People who are immunocompromised who got the single-dose Johnson & Johnson shot should get a booster at least two months after their initial vaccine. People who choose a Moderna vaccine as a booster, even if they received a different vaccine as the first dose, should get the half-dose sized shot that was authorized as a booster for Moderna's vaccine, the CDC said.Even if they are vaccinated, the CDC recommends people with conditions that compromise their immune systems should still try to avoid crowds and poorly ventilated spaces, and should wear a mask in indoor public spaces.

The U.S. Centers for Disease Control and Prevention has removed updated COVID-19-related guidance for the holiday season from its website just days after posting it.

Over the weekend, the CDC's website showed it updated its holiday guidance on Friday, but the web pages detailing the guidance were removed as of Monday.

"The page had a technical update on Friday, but doesn’t reflect the CDC’s guidance ahead of this upcoming holiday season. The CDC will share additional guidance soon," reads a statement sent to ABC News from the CDC Media Branch.

The vague guidance recommended virtual and outdoor guidance for holidays.

"My guess is that they put a little bit too much of the cart before the horse," said Dr. Katherine Gergen Barnett, of Boston Medical Center. "I know it's a frustration for people, so I think continuing to be in dialogue with trusted health professionals is a terrific way to go, as well."

The CDC's latest move adds to the confusion surrounding the holiday safety after Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Sunday that it was too soon to tell whether people should avoid gathering for Christmas.

On Monday, the nation's top infectious disease expert made an effort to clear the air on his previous statement.

"I will be spending Christmas with my family," Fauci said. "I encourage people, particularly the vaccinated people who are protected, to have a good, normal Christmas with your family."

Top health officials are emphasizing the importance of COVID-19 vaccinations in ensuring safe holiday gatherings, especially as doctors anticipate vaccine approvals for younger children.

"The good news is I think we're in a very different place than we were one year ago," Gergen Barnett said.

The CDC has given no timeline for updated holiday guidance.

Ivermectin has been called a wonder drug, and some people are wondering if it can, or should, be used to treat COVID-19. While misinformation flies online, the Centers for Disease Control and Prevention warn against using the drug.

The idea of using Ivermectin as a COVID-19 treatment started as a video emerged of a chairperson in the Japanese Medical Association saying he recommended doctors in Japan start using the drug to treat COVID-19.

RELATED: Butler Co. judge orders doctors to treat COVID-19 patient with Ivermectin

Many posts online containing the video make it seem like the video was filmed in August, however it was filmed in February. Seven months later and Japan has not approved of Ivermectin to be used to treat COVID-19.

While it hasn't been approved to treat COVID-19, the Food and Drug Administration has approved Ivermectin to treat infections caused by parasites. COVID-19 however, is not an illness caused by parasites.

The CDC said since early July, Ivermectin prescription fills went up "24-fold" despite a warning from the organization that improper usage or dosage could cause serious health issues.

The CDC said one patient was hospitalized for nine days with hallucinations, confusion, rapid breathing and tremors after drinking one dose meant for cattle. Another patient five tablets of unknown strength for five days and was disoriented and had difficulty answering questions until they were hospitalized and taken off the drug.

Small sample studies have been performed to look at the efficacy of Ivermectin on COVID-19, but those studies haven't shown conclusive evidence of the drug's benefit for the pandemic.

"Maybe someday a larger study may show some benefit," Dr. Steve Feagins with Mercy Health said. "But so far there's really not in the, and there's more harm than, than benefit."

Clinical trials are underway in Florida, including studies to determine if Ivermectin is effective for high risk patients in preventing hospitalizations, but so far the FDA has not approved the drug to treat COVID-19 and the FDA and CDC warn against its use.

RELATED: Hearing set in case of West Chester hospital ordered to treat COVID-19 patient with Ivermectin

CINCINNATI — President Joe Biden visited the Tri-State Wednesday to talk about infrastructure and the economy among other things, but a few of the president's statements were outright wrong or factually false.

One of the things the president discussed was gun violence in the Tri-State.

Biden said, "You've had a lot of gun violence here in Cincinnati. I think it's up to what, how many dead? Five hundred over a period? Don't hold me to the number whatever it was."

However, according to Cincy Insights, there haven't been 500 shootings in Cincinnati so far in 2021. There have been 191 reported shootings in the city, and 39 of them were deadly. Even if the time frame is extended to the last five years, the data shows there have been 278 deadly shootings.

While one deadly shooting is too many, the president saying there have been 500 deadly shootings is wrong.

The president also said, "We're not in a position where we think that any virus, including the delta virus, which is much more transmissible and more deadly in terms of non- unvaccinated people... the various shots that people are getting now cover that. They're, you're okay. You're not going to, you're not going to get COVID if you have these vaccinations."

That's false. Vaccinated people can still get COVID-19. A couple from the Tri-State were both vaccinated, but they both contracted the delta variant.

"A lot of folks I know got the vaccine, and they're like, 'OK. It's all over,' but, clearly it's not," Rachelle Caplan said. "We still should be being cautious for ourselves and other people."

The Centers for Disease Control and Prevention reported in July that 5,492 people who died or were hospitalized with COVID-19 were vaccinated. However, the CDC also said more than a quarter of hospitalizations were asymptomatic or not related to COVID-19, and about a quarter of those who died were found to be the same.

Finally, Biden commented on bridges and infrastructure.

"Take a look at Ohio and Kentucky," Biden said. "Combined, there's well over, there are thousands of bridges that need repair."

According to the Federal Highway Administration, there are about 42,000 bridges in Ohio and Kentucky and 2,400 of them are in "poor condition." The maligned Brent Spence Bridge actually falls into the "fair" category per the administration.

The U.S. Centers for Disease Control and Prevention on Friday warned people who are immunocompromised that the COVID-19 vaccine may not have been effective for them and encouraged them to take precautions as if they were not vaccinated."People who are immunocompromised should be counseled about the potential for reduced immune responses to COVID-19 vaccines and to follow current prevention measures (including wearing a mask, staying 6 feet apart from others staying they don't live with, and avoiding crowds and poorly ventilated indoor spaces) to protect themselves against COVID-19 until advised otherwise by their healthcare provider," according to the CDC's website.The CDC did not go so far as to tell the millions of immunocompromised people in the U.S. to get an additional shot of a COVID-19 vaccine, noting that "the safety, efficacy and benefit of additional doses for COVID-19 vaccines in immunocompromised persons continues to be evaluated."A federal official told CNN that "CDC is looking into ongoing research exploring the possibility that immunocompromised could benefit from an additional dose."Some immunocompromised people have, on their own, received additional doses of the vaccine, and a study last month by Johns Hopkins researchers suggested that an extra shot may help increase COVID-19 antibody levels for some organ transplant recipients who did not have a full response to their original vaccinations.On Sunday, Dr. Anthony Fauci, President Joe Biden's chief medical adviser, acknowledged the reality that some people are acting ahead of official recommendations, noting that there are individual physicians "right now that are saying, 'I want to go the extra mile with someone who might have a lower level of immunity.'"On Friday, the CDC said data suggest the response to the vaccines might be reduced for several groups, including organ transplant recipients, people who are receiving chemotherapy for cancer, people who have certain blood cancers, and people receiving dialysis or taking certain medications that suppress the immune system.The CDC's Advisory Committee on Immunization Practices is scheduled to discuss additional doses for immunocompromised individuals during its meeting on July 22.

We've talked a lot about health equity with the pandemic disproportionately impacting lower income and communities of color.

Now, the Centers for Disease Control and Prevention (CDC) has a new initiative to deliver an important preventive health care tool to rural and smaller neighborhoods.

It’s a new fluoride tablet system that works similar to chlorine tablets in a pool, but it's designed for small public water systems.

Currently, about 35% of Americans don't have access to properly fluoridated water. That's mostly because they live in an area that doesn't have the money or technology to maintain these systems.

The new tablet system could reach nearly 32,000 small public utilities, often in rural or undeserved areas that serve about 19 million people.

Research has long shown that fluoridated water reduces cavities in children and adults, and the pandemic has likely enhanced America’s dental health and equity problem.

“Their hygiene practices have changed. Their dietary habits have changed. They are snacking more, snacking on sugar products more. And some unfortunately have chosen to defer going to the dentist,” said Dr. Howard Pollick, with the American Dental Association and the UCSF School of Dentistry.

The American Dental Association sees this new fluoride tablet system as a game changer for overall dental health and equity.

On top of access to dental care, some communities have barriers to basic messaging about good oral hygiene, like brushing twice a day.

“It’s very important that they be seen by members of the public as somebody that they can trust, so maybe who speaks their language, maybe who is a similar age, similar race or ethnicity,” said Dr. Pollick.

A federal health study found a daunting shortage of dentists of color. Less than 10% are Black or Hispanic. It's something that is slowly improving, but bridging the gap requires larger, more purposeful approaches, including an overhaul of the current economics of dental practice.

Despite being a front-line health care worker and witnessing firsthand the impacts of the COVID-19 crisis, registered nurse Deborah Torres was concerned about getting vaccinated for the virus.

“I wanted to see how my other coworkers that were working and getting vaccinated did,” she said.

Torres waited a month after it became available, then got the Moderna shot, which she says caused some physical side effects.

“I got the chills, nausea, dizziness,” she said. “I had a fever, and I was very fatigued and that lasted for an entire day.”

Torres works at a major hospital in Southern California, where many of her coworkers are still reluctant to get vaccinated

“It’s not that they’re anti-vaccine, it’s just that they’re hesitant right now because it’s new,” she said.

A new study by the Kaiser Family Foundation in partnership with The Washington Post found 48% of front-line health care workers are unvaccinated, which is concerning for some medical experts.

“It’s also a patient safety issue. If you get vaccinated, you’re much less likely to give COVID in the workplace,” said William Schaffner, MD, an infectious disease specialist with Vanderbilt University Medical Center and a consultant for the Centers for Disease Control and Prevention.

Schaffner understands the concerns health care workers have about getting vaccinated, but says when they don’t, it could increase transmission rates and also impact others’ decisions.

“If the nurses don’t get vaccinated and people ask them and they discover that the nurses are weary, of course, because nurses are trusted, the neighbors and friends will be weary of getting vaccinated also,” he said.

While Torres did get vaccinated, she still supports her coworkers that haven’t

“I don’t have any judgment towards them, and I don’t think any differently of them,” she said.

The Centers for Disease Control and Prevention (CDC) announced on Thursday that people who are fully vaccinated against COVID-19 no longer need to wear a face mask indoors or practice social distancing, "except where required by federal, state, local, tribal, or territorial laws, rules, and regulations, including local business and workplace guidance."The nation was shocked, to say the least. Yes, that means fully vaccinated folks can now go maskless at indoor events, inside restaurants, during exercise classes, and at worship gatherings. (Major caveat: Masks are still required on public transportation, plus in crowded, high-risk places like hospitals and homeless shelters.)"I wouldn’t go so far as to say essentially over," Anthony Fauci, M.D., director of the U.S. National Institute of Allergy and Infectious Diseases, said in an interview with CNN."I think this is a very important step in the direction of trying to get back to some degree of normality. Because this is something that everyone has had on their mind … and being able to go around without a mask indoors as well as outdoors is really a big step in that direction."However, many people feel confused by the sudden change, especially after more than a year of strict mask mandates. Understandably, there’s also concern that there’s no way to tell who, exactly, is vaccinated. Since we haven’t reached the threshold for herd immunity (only 35% of Americans are currently fully vaccinated), concerns have been raised for children under 12, who cannot yet be immunized, as well as those who are immunocompromised and rely on others to get their shot.CDC Director Rochelle Walensky, M.D., explained the reasons behind the decision during a White House COVID-19 response team briefing, and it boils down to these three factors: The COVID-19 vaccines are incredibly effective.According to phase 3 clinical trial data, the Pfizer-BioNTech vaccine is 95% effective at preventing symptomatic COVID-19, while the Moderna vaccine is about 94% effective and the single-dose Johnson & Johnson vaccine is 66% effective. Real-world data (collected from people outside of a clinical trial setting) has shown similar results. According to research published by the CDC, data from nearly 4,000 health care personnel, first responders, and other frontline workers from eight locations across the country show that both mRNA vaccines from Moderna and Pfizer are 90% effective 14 days or more after the second dose. A pre-print study published at the end of April examined the real-world effectiveness of the Johnson & Johnson vaccine in more than 1,700 people in Minnesota, Arizona, Florida, Wisconsin, and Iowa, and found that it was nearly 77% effective at preventing symptomatic illness. It’s still important to note that you can still get COVID-19 after being fully vaccinated."The vaccines, even at their best, are 95% effective," says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. The CDC has data on these "breakthrough infections," noting that there were 9,245 reported COVID-19 cases out of more than 95 million fully vaccinated Americans as of April 26.This is not unexpected, the CDC says, and to ensure that the data continues to be as useful as possible, the agency is "transitioning to reporting only patients with COVID-19 vaccine breakthrough infections that were hospitalized or died," as a majority of people who are vaccinated and contract the virus will have mild symptoms or none at all.Research shows the vaccines are also largely effective against coronavirus variants. Variants have gotten a lot of attention, but "the vaccines have shown good efficacy to the strains currently circulating in the U.S.," says Richard Watkins, M.D., an infectious disease physician and a professor of internal medicine at the Northeast Ohio Medical University. Data shared from Pfizer in March revealed that its vaccine was 97% effective at preventing symptomatic COVID-19, hospitalization, and deaths in people in Israel—a country where more than 80% of positive COVID-19 cases were driven by B.1.1.7, the highly infectious variant that was first detected in the U.K. In April, Pfizer also announced that its vaccine was 100% effective in preventing COVID-19 cases in South Africa, where the B.1.351 variant dominated; it also seems to be highly effective against the P.1 variant, which was first detected in Brazil, with researchers writing that the effectiveness is "roughly equivalent" to that of the vaccine against B.1.1.7. Moderna shared in January that the B.1.1.7 strain had "no significant impact" on neutralizing titers—antibodies in the blood that closely correlate with how effective a vaccine is. And despite a six-fold reduction in these infection fighters with B.1.351., the antibody levels still remained higher than what’s expected for protection against severe illness. The Johnson & Johnson was tested in clinical trials in several areas around the world when many variants were rampant. The efficacy is slightly different among the countries studied, suggesting that variants may make a difference.In the U.S., for example, efficacy of the Johnson & Johnson vaccine was 74%, while the efficacy was 66% in Brazil. In South Africa, it was 52%. Overall, the vaccine protected against severe or critical disease up to 82% of the time. The vaccines likely help prevent people from spreading COVID-19 to others.A growing body of evidence suggests that people who are fully vaccinated against COVID-19 are less likely to have a symptomatic infection and to pass SARS-CoV-2 to others should they be carrying the virus. Based the current data, "it’s unlikely that fully vaccinated people will infect others," Dr. Schaffner confirms.Preliminary data from Israel suggest that people vaccinated with the Pfizer vaccine who develop COVID-19 have a four-times lower viral load (the amount of virus they have in their body) than people who are unvaccinated, suggesting that they’re much less likely to transmit the virus. "This seems to be less of a risk than we originally thought," Dr. Schaffner says. Data is not yet available for other vaccines at this time, so the CDC will continue to monitor the research as it continues.Even with a growing amount of evidence, it’s understandable if you still prefer to wear a mask.Timothy Murphy, M.D., senior associate dean for clinical and translational research at the University at Buffalo in New York, calls the new masking guidelines a "huge, bold change," pointing out that "a lot depends on the honor system."After all, there’s no way to know if another person is vaccinated, unless you have a conversation about it. That may be easier with people you know, but not likely to happen with strangers."When you go into a crowd and there are many people not wearing masks, it’s a very safe environment if they’re all vaccinated," Dr. Murphy explains. But that level of safety does dip if there are plenty of unvaccinated people not wearing masks in the bunch, so he "understands why people might be a bit nervous" about the lifted mandate.So, if you wish to continue to wear a face mask until public health experts have presented a clearer picture of the pandemic at large, Dr. Schaffner says you should do what makes you comfortable, even if you are vaccinated.After all, research shows it protects both the wearer and the people around them — and for now, being extra cautious certainly doesn’t hurt.

ATLANTA — The Centers for Disease Control and Prevention (CDC) issued a

health alert

Saturday, warning against the use of non-pharmaceutical chloroquine phosphate to treat COVID-19.

Chloroquine phosphate is a chemical for aquarium use because it kills algae. It's commercially available for purchase at stores and online.

The national health alert comes after a Phoenix-area man died and his wife was hospitalized after taking the chemical they believed could help protect against coronavirus.

Last Sunday, the couple, both in their 60s, took the aquarium-use chemical, and within 30 minutes, the two experienced severe side effects, requiring admittance to a nearby hospital. The man died, and his wife remains under critical care, according to a hospital spokesperson.

The product in their possession was in powder form inside a 2.2-lb. container and labeled "for Ornamental Fish Use Only."

A family friend told

Phoenix station KNXV-TV

that the couple decided to mix the powder with a drink because they had heard the president and other officials touting the drug chloroquine as a possible treatment for COVID-19.

The CDC says there are currently no FDA-approved drugs that can treat COVID-19.

"Pharmaceutical chloroquine phosphate and hydroxychloroquine sulfate are approved by the FDA to treat specific medical conditions, such as malaria, lupus, and rheumatoid arthritis. Currently, these medications are being studied and evaluated as treatment for COVID-19; however, their efficacy to either prevent or treat this infection are unknown," the CDC statement read.

The CDC says it is also aware of unconfirmed media reports that these commercially available aquarium-use chemicals may be out of stock due to potential increased demand by the public.