You asked, we?re answering: Your top questions about Covid-19 and vaccines

But since Covid-19 vaccines are so new, it’s not clear how long immunity from the vaccines will last.“So far, we can’t say for sure,” CNN Chief Medical Correspondent Dr. Sanjay Gupta said. But Moderna says its vaccine may be able to prevent infection and transmission.“Both the vaccines – both the Pfizer and the Moderna vaccines – have been shown to be efficacious and very safe in the clinical trials that have been conducted to date,” said Dr. Rick Bright, a member of president-elect Joe Biden’s coronavirus advisory board. “Many of the vaccines that we’ve made in history are actually stronger than the virus is itself at creating immunity.” The immunity you get from contracting Covid-19 does last for a certain amount of time, but the nature of the vaccine should provide longer immunity, CNN Chief Medical Correspondent Dr. Sanjay Gupta said. AHA President Dr. Mitchell Elkind said cardiac complications of Covid-19 could linger after recovering from coronavirus.“You can certainly get both the flu and Covid-19 at the same time, which could be catastrophic to your immune system,” said Dr. Adrian Burrowes, a family medicine physician in Florida.In fact, getting infected with one can make you more vulnerable to getting sick with the other, epidemiologist Dr. Seema Yasmin said. “Your defenses go down, and it makes you vulnerable to getting a second infection on top of that.”On their own, both Covid-19 and the flu can attack the lungs, potentially causing pneumonia, fluid in the lungs or respiratory failure, the Centers for Disease Control and Prevention said.“The two (illnesses) together definitely could be more injurious to the lungs and cause more respiratory failure,” said Dr. Michael Matthay, a professor of medicine at the University of California, San Francisco.And just like with Covid-19, even young, healthy people can die from the flu.The good news is there are easy ways to help avoid a flu/Covid-19 double whammy: get a flu vaccine, stay 6 feet away from anyone outside your household, and wear a face mask anytime you might be in close contact with others. The precautions you take against Covid-19 can “doubly protect us from both of those viruses,” Yasmin said.Both the flu and Covid-19 can give you a fever, cough, shortness of breath, fatigue, sore throat, body aches and a runny or stuffy nose, the CDC said.“Some people may have vomiting and diarrhea, though this is more common in children than adults,” the CDC said.But unlike the flu, Covid-19 can cause a loss of taste or smell.And about half of coronavirus transmissions happen before any symptoms show up. “There’s good enough data to say that aerosol transmission [of coronavirus] does occur,” Fauci saidMultiple case studies suggest coronavirus can spread well beyond 6 feet through airborne transmission, such as during choir practices, said Dr. Amy Compton-Phillips, chief clinical officer of Providence Health System. In July, 239 scientists backed a letter urging public health agencies to recognize the potential for aerosolized spread.“There is significant potential for inhalation exposure to viruses in microscopic respiratory droplets (microdroplets) at short to medium distances (up to several meters, or room scale), and we are advocating for the use of preventive measures to mitigate this route of airborne transmission,” the letter said.Fauci said there’s an easy way to help minimize the risk: “Wear the mask.”The CDC says face masks should have two or more layers of breathable fabric.Research is still evolving, but a recent study examining antibodies suggests you could be immune for months after infection. “These face masks are the most important, powerful public health tool we have,” CDC director Dr. Robert Redfield said.He most people probably won’t be able to get vaccinated until mid-2021. Even then, “as we go through the vaccination period … we still need to use masks,” said Dr. Eric Topel, founder and director of the Scripps Research Translational Institute.If at least 95% of people in every state consistently wore masks in public, it could save almost 130,000 US lives through the end of February 2021, researchers said in a study published in Nature Medicine.More than 40% of US adults have at least one underlying condition that can put them at higher risk of severe complications, according to the CDC. People who have cancer, an organ transplant, sickle cell anemia, poorly controlled HIV or any autoimmune disorder are also at higher risk.Covid-19 patients with pre-existing conditions — regardless of their age — are 6 times more likely to hospitalized and 12 times more likely to die from the disease than those who had no pre-existing conditions, CNN Chief Medical Correspondent Dr. Sanjay Gupta said. The letters and numbers in “Covid-19” come from “Coronavirus disease 2019.”About 2% to 5% of babies born to mothers with Covid-19 tested positive for coronavirus within the first four days of life, according to the American Academy of Pediatrics.But infected mothers are unlikely to pass coronavirus to their newborns when appropriate precautions are taken, according to a study published in The Lancet Child & Adolescent Health.In that study, researchers found no cases of viral transmission among 120 babies born to 116 mothers with coronavirus — even when both shared a room and the mothers breastfed.But the babies remained 6 feet apart from their mothers, except while breastfeeding. The moms also wore surgical masks when handling their newborns and followed proper hand and breast washing procedures.The novel coronavirus is one of seven coronaviruses that have been known to infect humans — including SARS, MERS, and some that are linked to the common cold.It’s too early to say whether some people might get long-term immunity with the new coronavirus. But with “common cold coronaviruses, you don’t actually have immunity that lasts for very long,” said Dr. Celine Gounder, a professor of medicine and infectious diseases at the New York University School of Medicine.The Crisis Text Line is available texting to 741741. “With all the heavy breathing, you may even want to double the usual 6 feet to 12 feet, just to be safe,” CNN Chief Medical Correspondent Dr. Sanjay Gupta said.For symptomatic carriers: If it’s been at least 10 days since your symptoms started and at least 24 hours since you’ve had a fever (without the help of fever-reducing medication) and your other symptoms have improved, you can go ahead and stop isolating, the CDC says.Patients with severe illness may have to keep isolating for up to 20 days after symptoms started.(But it’s important to note symptoms typically don’t show up until several days after infection — and you can be more contagious during this pre-symptomatic time. At that point, it’s very unlikely they are still contagious.Doctors say wearing eye protection (in addition to face masks) could certainly help some people, but it’s not necessary for everyone.Teachers who have younger students in the classroom are “likely to be in environments where children might pull down their masks, or not be very compliant with them,” epidemiologist Saskia Popescu said. “There is concern that you could get respiratory droplets in the eyes.”If you’re a health care worker or taking care of someone at home who has coronavirus, it’s smart to wear eye protection, said Dr. Thomas Steinemann, clinical spokesperson for the American Academy of Ophthalmology.(Note: Regular glasses or sunglasses aren’t enough, because they leave too many gaps around the eyes.)But if you’re not in a high-risk situation — and you’re very strict about wearing face masks and staying 6 feet away from others – wearing goggles isn’t necessary.While it’s still possible to get Covid-19 through the eyes, that scenario is less likely than getting it through your nose or mouth, Steinemann said.He said if a significant number of people were getting coronavirus through their eyes, doctors would probably see more Covid-19 patients with conjunctivitis, also known as pink eye (though having pink eye doesn’t necessarily mean you have coronavirus).The CDC does not recommend using plastic face shields for everyday activities or as a substitute for face masks. “Cloth face coverings are a critical preventive measure and are most essential in times when social distancing is difficult,” the CDC says.Clinical and laboratory studies show cloth face coverings reduce the spray of droplets when worn over the nose and mouth – what the CDC refers to as “source control.” And many people are contagious even when they don’t have any symptoms and don’t know they’re infected. The study – which examined test results following a camp that more than 600 campers 120 staffers attended – found that 51% of those ages 6 to 10 tested positive; 44% of those ages 11 to 17 tested positive; and 33% of those ages 18 to 21 tested positive.“This investigation adds to the body of evidence demonstrating that children of all ages are susceptible to SARS-CoV-2 infection and, contrary to early reports, might play an important role in transmission,” wrote the CDC study’s authors.Children can be more reluctant because they’re more sensitive to new things than adults are, said Christopher Willard, a psychiatry lecturer at Harvard Medical School.“There’s also the weird psychological aspect of not being able to see their own face or other people’s faces and facial expressions,” which can hinder their feelings of comfort or safety, he said.To ease their mask fears, try buying or making masks with fun designs on them. Show your children your own mask, and let them know that by wearing one, they’ll be just like Mom or Dad.Yes. And please do so, doctors say.This year, it’s “more important than ever to get a flu shot because we will almost certainly face the double whammy of flu season coinciding the same time as surging cases of COVID-19,” emergency room physician Dr. Leana Wen said. “People need to know that wearing masks can reduce transmission of the virus by as much as 50%, and those who refuse are putting their lives, their families, their friends, and their communities at risk,” said Dr. Christopher Murray, director of the University of Washington’s Institute for Health Metrics and Evaluation.If you traveled internationally, the CDC says you should stay home for 14 days after returning home. “Because travel increases your chances of getting infected and spreading COVID-19, staying home is the best way to protect yourself and others from getting sick,” the CDC says.You can read the CDC’s full guide on how to protect yourself on different types of transportation here.Unlike SARS and swine flu, the novel coronavirus is both highly contagious and especially deadly, CNN Chief Medical Correspondent Dr. Sanjay Gupta said. And in fact – a little bit strangely in this case — people tend to be the most contagious before they develop symptoms, if they’re going to develop symptoms,” CNN Chief Medical Correspondent Dr. Sanjay Gupta said.“They call that the pre-symptomatic period. And then you’ll touch other surfaces, and then you will be spreading virus if you are infected and shedding asymptomatically.”That’s why health officials suggests people wear face masks while in public and when it’s difficult to stay 6 feet away from others.The odds of transmitting coronavirus through sex hasn’t been thoroughly studied, though it has been found to exist in men’s semen.But we do know Covid-19 is a highly contagious respiratory illness that can spread via saliva, coughs, sneezes, talking or breathing — with or without symptoms of illness.So three Harvard physicians examined the likelihood of getting or giving Covid-19 during sex and made several recommendations. “Alcohol is pretty effective at killing germs, but it doesn’t wash away stuff,” said Dr. John Williams, a virologist at the University of Pittsburgh Medical Center Children’s Hospital of Pittsburgh.“If somebody’s just sneezed into their hand, and their hand is covered with mucus, they would have to use a lot more alcohol to inactivate that bacteria or virus.”A study published in The New England Journal of Medicine found that people with Type A blood have a higher risk of getting infected with coronavirus and developing severe symptoms, while people with Type O blood have a lower risk – but the study has caveats.The researchers cannot say if blood type is a direct cause of the differences in susceptibility. You never would tell somebody who was Type O that they were at smaller risk of infection.”The bottom line: “All of us are susceptible to this virus,” said Dr. Maria Van Kerkhove, technical lead for the World Health Organization’s Covid-19 response.“It’s probably safe if you’re not at home,” said Dr. Leana Wen, an emergency room physician. “Spraying disinfectants can result in risks to the eyes, respiratory or skin irritation,” the World Health Organization said.“Spraying or fumigation of outdoor spaces, such as streets or marketplaces, is also not recommended to kill the COVID-19 virus or other pathogens because disinfectant is inactivated by dirt and debris, and it is not feasible to manually clean and remove all organic matter from such spaces,” the WHO said.“Moreover, spraying porous surfaces, such as sidewalks and unpaved walkways, would be even less effective.” Besides, the ground isn’t typically a source of infection, the WHO said.And once the disinfectant wears off, an infected person could easily contaminate the surface again.Any large gathering can increase the spread because this coronavirus is transmissible by talking or even just breathing. And when people are “shouting and cheering loudly, that does produce a lot of droplets and aerosolization that can spread the virus to people,” said Dr. James Phillips, a physician and assistant professor at George Washington University Hospital.So doctors and officials say it’s extremely important to wear a face mask and try to keep your distance from others as much as possible.“To date, there is no evidence that very high vitamin D levels are protective against COVID-19 and consequently medical guidance is that people should not be supplementing their vitamin D levels beyond those which are currently recommended by published medical advice,” wrote Robin May, director of the Institute of Microbiology and Infection at the University of Birmingham in the UK. For anyone over 70 years of age in the US, the recommended daily intake goes up to 20 mcg/800 IU per day.But too much vitamin D can lead to a toxic buildup of calcium in your blood that can cause confusion, disorientation, heart rhythm problems, bone pain, kidney damage and painful kidney stones.“Viruses can live on surfaces and objects — including on money — although your chance of actually getting COVID-19 from cash is probably very low,” emergency medicine physician Dr. Leana Wen said.The new coronavirus can live for up to 72 hours on stainless steel and plastic, up to 24 hours after landing on cardboard, and up to four hours after landing on copper, according to a study funded by the US National Institutes of Health. If you can’t wash your hands immediately, use hand sanitzier or disinfectant.And since Covid-19 is a respiratory disease, make sure you avoid touching your face.It appears unlikely, but the CDC advises taking precautions.Experts believe coronavirus is mainly spread during close contact (about 6 feet) with a person who is currently infected, the CDC said.“This type of spread is not a concern after death,” the CDC said. If your hair is not falling into your face or you’re not running your fingers through it, then there is less of a risk.”If your hair does fall into your face, you may want to pull it back to minimize your risk, King said.As for facial hair, “washing at least daily if not more frequently is wise, depending on how often they touch their face,” Aronoff said.There have been some reports of animals infected with coronavirus — including two pets in New York and eight big cats at the Bronx Zoo. Most of those infections came from contact with humans who had coronavirus, like a zoo employee who was an asymptomatic carrier. So soap or alcohol are very, very effective against dissolving that greasy liquid coating of the virus.”By cutting through the greasy barrier, Williams said, “it physically inactivates the virus so it can’t bind to and enter human cells anymore.”Yes, coronavirus can live on the soles of shoes, but the risk of getting Covid-19 from shoes appears to be low.A report published by the CDC highlighted a study from a hospital in Wuhan, China, where this coronavirus outbreak began. Even if coronavirus does get into your food, your stomach acid would kill it, said Dr. Angela Rasmussen, a virologist at Columbia University.“When you eat any kind of food, whether it be hot or cold, that food is going to go straight down into your stomach, where there’s a high acidity, low-pH environment that will inactivate the virus,” she said.But it’s a good idea to disinfect the takeout containers, CNN Chief Medical Correspondent Dr. Sanjay Gupta said. So if you’re moving as human body through the air … (it’s) unlikely to stick to your clothes.”It’s easy for asymptomatic people to spread coronavirus, said Anne Rimoin, an epidemiology professor at UCLA’s School of Public Health.“When you speak, sometimes you’ll spit a little bit,” she said. In a study from China, where the first Covid-19 outbreak occurred, smokers were 14 times more likely to develop severe complications than non-smokers.Even occasionally smoking marijuana can put you at greater risk.“What happens to your airways when you smoke cannabis is that it causes some degree of inflammation, very similar to bronchitis, very similar to the type of inflammation that cigarette smoking can cause,” said pulmonologist Dr. Albert Rizzo, chief medical officer for the American Lung Association.“Now you have some airway inflammation, and you get an infection on top of it. And about half of Americans don’t get vaccinated – including most children who die from the flu.The CDC changed its guidance on wearing face masks as more studies about asymptomatic spread piled up.Now, the CDC “recommends wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies).”But there are several important caveats and key points: An antiviral drug must be able to target the specific part of a virus’ life cycle that is necessary for it to reproduce, according to Harvard Medical School.“In addition, an antiviral drug must be able to kill a virus without killing the human cell it occupies. “So that could happen in the case of health care workers who are exposed to a lot more Covid-19 as a result of their work — that they get more severely ill.”In one study, about 4 in 5 people with confirmed coronavirus in China were likely infected by people who didn’t know they had it, according to research published in the journal “Science.”“These findings explain the rapid geographic spread of (coronavirus) and indicate containment of this virus will be particularly challenging,” researchers wrote.In mid-March, the CDC said almost half of the 712 people with coronavirus who were on the Diamond Princess cruise ship didn’t have any symptoms when they tested positive.Other studies suggest 25% to 50% of coronavirus carriers don’t have symptoms.In the US, “I think it could be as many as 1 in 3 walking around asymptomatic,” said New Jersey primary care physician Dr. Alex Salerno.“We have tested some patients that have known exposure to COVID (coronavirus disease). “The vast majority of people – about 80% – will do well without any specific intervention,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.Those patients should get plenty of rest, hydrate frequently and take fever-reducing medication.“The current guidance – and this may change – is that if you have symptoms that are similar to the cold and the flu and these are mild symptoms to moderate symptoms, stay at home and try to manage them,” said Dr. Patrice Harris, president of the American Medical Association. Fauci said he and his wife are still drinking tap water.The Harvard Medical School offers several tips, including: You can’t, said Dr. James Phillips, chief of disaster and operational medicine at George Washington University Hospital.“We’re so far behind on testing, there’s only one way we can be certain not to transmit the virus and be certain not to get it ourselves: We need to start treating every person as though they have this, ” Phillips said. And we’re not sure when they start spreading it.” That’s why it’s so critical to avoid crowds, stay at least 6 feet away from others, wear a mask when you might be in close contact with others, wash or disinfect your hands, and stop touching your face.It may be difficult to know whether your loved one has coronavirus or another illness. Wash your hands frequently and avoid sharing personal items with the infected person.If you think you’re developing symptoms, stay home and call your physician.“I would suggest wiping down external surfaces of canned or wrapped foods,” said Dr. Celine Gounder, an infectious disease specialist at Bellevue Hospital Center. Ask your physician to call the local or state health department, too, so they’re aware you’re being monitored for the virus.Stay at least 6 feet away from others, wear a face mask when in public or when you’re close to people who don’t live with you, wash your hands often, and stop touching your face. “Even though the new coronavirus can stay on surfaces for a few hours or up to several days (depending on the type of surface), it is very unlikely that the virus will persist on a surface after being moved, travelled, and exposed to different conditions and temperatures,” WHO said.