Air travel can carry many risks for people with disabilities, one of which is the loss or damage of wheelchairs. According to the Air Travel Consumer Report, how many wheelchairs or scooters were lost, damaged, delayed or stolen on the country’s largest airlines in 2021?

Nearly half of the participants of a recent study who were menstruating regularly at the time of the survey reported heavier bleeding during their periods after receiving the Covid-19 vaccine. Others who did not typically menstruate — including transgender men, people on long-acting contraceptives, and post-menopausal women — also experienced unusual bleeding.The new study — the largest to date — expands on research that has highlighted the temporary effects of Covid-19 vaccines on menstrual cycles, but until now focused primarily on cisgender women who menstruate.Although the vaccines have largely prevented deaths and severe disease with few reported side effects, many medical experts initially brushed aside concerns when women and gender-diverse people started reporting erratic menstrual cycles after receiving the shots.To get a better sense of these post-vaccination experiences, researchers at the University of Illinois at Urbana-Champaign and Washington University School of Medicine in St. Louis distributed an online survey in April 2021 to thousands of people across the globe. After three months, the researchers collected and analyzed more than 39,000 responses from individuals between the ages of 18 and 80 about their menstrual cycles. All the survey respondents had been fully vaccinated — with the Pfizer-BioNTech, Moderna, Johnson & Johnson vaccines or another that had been approved outside the United States. And to the best of their knowledge, the participants had not contracted Covid-19 before getting vaccinated.The research, published Friday in the journal Science Advances, shows that 42 percent of people with regular menstrual cycles experienced heavier bleeding after vaccination, while 44 percent reported no change and 14 percent reported lighter periods. Additionally, 39 percent of respondents on gender-affirming hormone treatments, 71 percent of people on long-acting contraceptives and 66 percent of postmenopausal women experienced breakthrough bleeding after one or both of their shots.“I think it’s important that people know this can happen, so they’re not scared, they’re not shocked and they’re not caught without supplies,” said Katharine Lee, a biological anthropologist at the Washington University School of Medicine in St. Louis, and the study’s first author.Dr. Lee cautioned, however, that the study did not compare the results with a control group of people who did not get vaccinated. And it is possible that people who observed changes in their cycles after vaccination may have been more likely to participate in the survey. Still, the findings line up with smaller studies that have reported menstrual changes after vaccination with more robust controls.Importantly, the new study also found that some demographics may be more likely to experience menstrual changes, and the study may help them be better prepared, Dr. Lee said. A heavier menstrual flow was more likely for those who were older, for instance. Survey respondents who used hormonal contraception, had been pregnant in the past or had been diagnosed with a reproductive condition like endometriosis, fibroids or polycystic ovarian syndrome were also more likely to have heavier bleeding during their periods. People who identified as Hispanic or Latino tended to report heavier bleeding too. And people who experienced other side effects of the vaccines, like a fever or fatigue, also had a higher chance of experiencing erratic periods.Postmenopausal women who were slightly younger, around an average age of 60, were more likely to experience breakthrough bleeding after the vaccine than those who were older. But the type of vaccine postmenopausal women received, whether they had other side effects like a fever or whether they had a past pregnancy did not seem to have an effect on their bleeding.Why do these changes occur?Some level of variation in menstruation — the number of days you bleed, the heaviness of your flow and your cycle length — is normal.“Our menstrual cycles are not perfect clocks,” said Dr. Alison Edelman, a professor of obstetrics and gynecology at Oregon Health & Science University who has also studied the impact of Covid-19 vaccines on menstruation.Hormones secreted by the hypothalamus, the pituitary gland and the ovaries regulate the monthly cycle, and they can be affected by both internal and external factors. Stress and illness, weight loss or weight gain, calorie restriction and intense exercise can all change typical patterns of menstruation.The endometrium, which lines the uterus and is shed during menstruation, has also been linked to the immune system. Because of the role it plays in the remodeling of uterine tissue and offering protection against pathogens, it is possible that when vaccines activate the immune system, which is what they should be doing, they also somehow trigger downstream effects in the endometrium, causing a disturbance in your menstrual cycle, Dr. Edelman said. And some individuals may be more sensitive to immune or hormone changes in their body.In her research, Dr. Edelman found that some women’s periods came a day or two later than usual after they got vaccinated against coronavirus. But the changes were temporary — menstruation tended to return to normal after one or two cycles.What to do if you notice menstrual irregularities after the Covid vaccineIf you experience any new or unusual patterns of bleeding, take note of it. The menstrual cycle can be thought of as another vital sign, just like your body temperature or blood pressure, that provides clues about your health, said Dr. Jennifer Kawwass, a reproductive endocrinologist at Emory University, who was not involved in the study.“A significant change in menstrual cycle interval or bleeding profile warrants further investigation to be sure there is not an underlying endocrinologic, hematologic or anatomic cause,” Dr. Kawwass said. Breakthrough bleeding in people who no longer normally menstruate, for example, may also be a warning sign of cervical, ovarian, uterine or vaginal cancer.That being said, subtle variation in your menstrual cycle, if you have regular periods, should not be a cause for concern and does not require that you change anything you would normally do, Dr. Kawwass said.Clinical trials and other studies have already established that the Covid-19 vaccines are safe and effective and are unlikely to impact fertility in the long term.Should you get vaccinated at a certain time in your cycle?Experts agree that the chaos Covid-19 can cause throughout your body, including potential lingering effects, are far worse than any side effects caused by vaccination against the disease.People who have previously gotten a fever after a shot may plan their next dose on a day when they will not have to go in to work, Dr. Edelman said. But you should not let temporary menstrual changes prevent you from getting fully vaccinated or boosted. Since cases are on the rise again, delaying vaccination for two weeks or longer may significantly increase your risk of getting Covid-19, she said.Still, it’s important to track your body’s response to vaccination, and public health officials should acknowledge concerns about menstrual cycle variations in addition to warning people of the risk of getting Covid-19, said Keisha Ray, a bioethics expert at McGovern Medical School at UTHealth Houston.The increased transparency around menstrual changes or other side effects of vaccination could also have another benefit: reducing people’s vaccine hesitancy.“We’re trying to be truthful. We’re trying to validate peoples’ lived experiences,” said Dr. Lee. In turn, she hopes that the new research will help improve conversations around people’s health and lead to more inclusive clinical trials in the future.

Some reinfection questions, answered.If you’re one of the millions of Americans who have already had Covid-19, you may be wondering how long you will have immunity from the coronavirus. Earlier in the pandemic, most people assumed that getting infected had at least one upside: that you would be protected against future encounters with the virus. But as the latest wave heads toward the Western region of the country and the virus shows no signs of easing up, reinfections seem to have become common. Already, many people are reporting second or even third infections with newer variants.Experts have warned that exposure to the coronavirus — through vaccination or infection — does not mean that you are completely protected from future infections. Rather, the coronavirus is evolving to behave more like its closely related cousins, which cause common colds and infect people repeatedly throughout their lives.“I’ve thought, almost since the beginning of this pandemic, that Covid-19 is eventually going to become an inevitable infection that everybody gets multiple times, because that’s just how a new respiratory virus gets established in the human population,” said Dr. Amesh Adalja, an infectious-disease specialist at Johns Hopkins University.However, the coronavirus doesn’t yet fit into clear seasonal patterns like the other common cold viruses. It can also cause debilitating symptoms that persist for months or years in some people, and has claimed the lives of millions of others. So what can you do to protect yourself, not only from infection but also reinfection? We asked experts for answers to common questions.How long will my immunity last after getting Covid?Before Omicron, reinfections were rare. A team of scientists, led by Laith Abu-Raddad at Weill Cornell Medicine-Qatar, estimated that a bout with Delta or an earlier coronavirus strain was roughly 90 percent effective in preventing a reinfection in both vaccinated and unvaccinated people. “But Omicron really changed that calculus,” said Dr. Abu-Raddad, an infectious disease epidemiologist.After Omicron emerged, prior infections only provided about 50 percent protection against reinfection, Dr. Abu-Raddad’s study showed. The coronavirus had acquired so many mutations in its spike protein that newer versions became more transmissible and better able to evade immunity. That means you can catch a version of Omicron after recovering from an older, non-Omicron variant. You can even get sick with one of the newer Omicron subvariants after getting over a different version of it.Other factors also increase your vulnerability to reinfection, starting with how long it has been since you had Covid. Immune defenses tend to wane after an infection. A study published in October 2021 estimated that reinfection could occur as soon as 3 months after contracting Covid-19. While these findings were based on the genome of the coronavirus and accounted for expected declines in antibodies that could fight off the virus, the study did not account for new variants like Omicron that were radically different from older variants. Because of how different Omicron is, your protection may wane even sooner. In a study published in February that has not yet been peer-reviewed, scientists from Denmark found that some people got reinfected with the BA.2 sublineage of Omicron as soon as 20 days after they got infected with the original Omicron BA.1.Because the virus is infecting more people now, your chances of being exposed and getting reinfected are also higher, Dr. Abu-Raddad said. And while it’s unclear if some people are simply more susceptible to Covid-19 reinfection, researchers are beginning to find some clues. People who are older or immunocompromised may make very few or very poor quality antibodies, leaving them more vulnerable to reinfection, Dr. Abu-Raddad said. And early research shows that a small group of people have a genetic flaw that cripples a crucial immune molecule called interferon type I, putting them at higher risk of severe Covid symptoms. Further studies could find that such differences play a role in reinfection as well.For now, you should treat any new symptoms, including a fever, sore throat, runny nose or change in taste or smell, as a potential case of Covid, and get tested to confirm if you are positive again.Will subsequent infections be more or less severe?The good news is that your body can call on immune cells, like T cells and B cells, to quash a reinfection if the virus sneaks past your initial antibody defenses. T cells and B cells can take a few days to get activated and start working, but they tend to remember how to battle the virus based on previous encounters.“Your immune system has all kinds of weapons to try and stop the virus even if it gets past the front door,” said Shane Crotty, a virologist at the La Jolla Institute for Immunology in California.Many of these immune cells build up their protections iteratively, Dr. Crotty said. That means that people who are vaccinated and boosted are especially well equipped to duke it out with the coronavirus. Similarly, people who have been infected before are able to keep the virus from replicating at high levels if they get reinfected. And most people who have logged encounters with both the vaccine and the coronavirus build up a hybrid immunity that may offer the best protection.The result is that second or third infections are likely to be shorter and less severe.Dr. Abu-Raddad, who has been tracking reinfections among large groups of people in Qatar, has already started seeing this promising pattern in patient records: Of more than 1,300 reinfections that his team identified from the beginning of the pandemic to May 2021, none led to hospitalization in an I.C.U., and none were fatal.But just because reinfections are less severe, it doesn’t mean that they are not terrible. You may still run a fever and experience body aches, brain fog and other symptoms. And there’s no way of knowing if your symptoms will linger and become long Covid, Dr. Adalja said.It is possible that each Covid infection forces you into a game of Russian roulette, though some researchers hypothesize that the risk is highest right after your first infection. One of the risk factors for long Covid is having high levels of virus in your system early in an infection, and you are likely to have such a high viral load the first time you are infected, Dr. Abu-Raddad said. In subsequent infections, your body is better prepared to fight off the coronavirus so you may be able to keep the virus at low levels until it is completely cleared, he said.What can you do to reduce your risk of reinfection?Many of the tools and behaviors that help protect against infection can still help you avoid reinfection, Dr. Abu-Raddad said. “There is no magical solution against Covid reinfection.”Getting vaccinated and boosted, for example, is a good idea even after you’ve had Covid. You only need to wait a few weeks after an infection to get a shot. The vaccines will bolster your antibody levels, and research shows that they are effective in preventing severe outcomes if you get sick again. “Scientific confidence in vaccine-induced immunity was and is much higher than infection-induced immunity,” Dr. Crotty said.Additional measures, like masking indoors and in crowded spaces, social distancing and improving ventilation where possible, can provide another layer of protection. But because most people and communities have largely dropped these protections, it is up to individuals to decide when to adopt extra precautions based on their risk of getting Covid and how much they’d like to avoid it.“If you had an infection just last week, you probably don’t have to mask up,” Dr. Adalja said. “But as a month or so passes from your infection and new variants start circulating in the U.S., it may make sense for high risk individuals to do that. People who are trying to avoid getting Covid because they’re going on a cruise soon or because they need a negative P.C.R. test for some other reason may consider taking precautions. Covid protections don’t have to be one-size-fits-all.”What Questions Do You Have About Covid?

This viral illness is not like Covid, but there is cause for concern. Here’s how experts are thinking about it now.Health officials are tracking more than 100 cases of confirmed or suspected monkeypox that have appeared in countries where the disease does not typically occur, including Australia, Belgium, Canada, France, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, the United Kingdom and the United States.On Sunday, President Biden addressed the highly unusual cases, stating that “it is a concern in the sense that if it were to spread it would be consequential.” After more than two years of living through a pandemic, it is understandable that the news of a new virus spreading across the globe could cause alarm, but health experts say that monkeypox is unlikely to create a scenario similar to that of the coronavirus, even if more cases are found. “As surveillance expands, we do expect that more cases will be seen. But we need to put this into context because it’s not Covid,” Dr. Maria Van Kerkhove, the World Health Organization’s technical lead on Covid-19, said in a live online Q&A on Monday.Monkeypox is not a new virus, and it is not spread in the same way as the coronavirus, so we asked experts for a better understanding of the pathogen — and how the disease it causes is different from Covid-19.How contagious is monkeypox?People typically catch monkeypox by coming into close contact with infected animals. That can be through an animal bite, scratch, bodily fluids, feces or by consuming meat that isn’t cooked enough, said Ellen Carlin, a researcher at Georgetown University who studies zoonotic diseases that are transmitted from animals to humans.Although it was first discovered in laboratory monkeys in 1958, which gives the virus its name, scientists think rodents are the main carriers of monkeypox in the wild. It is primarily found in Central and West Africa, particularly in areas close to tropical rainforests — and rope squirrels, tree squirrels, Gambian pouched rats and dormice have all been identified as potential carriers.“The virus has probably been circulating in these animals for a very, very long time,” Dr. Carlin said. “And for the most part, it has stayed in animal populations.”The first human case of monkeypox was detected in 1970 in the Democratic Republic of Congo. Since then, the virus has periodically caused small outbreaks, though most have been limited to a few hundred cases in 11 African countries.A handful of cases have made it to other continents, brought by travelers or the import of exotic animals that passed the virus to house pets and then to their owners.But human-to-human transmission of monkeypox virus is pretty rare, Dr. Van Kerkhove said. “Transmission is really happening from close physical contact, skin-to-skin contact. So it’s quite different from Covid in that sense.”The virus can also spread by touching or sharing infected items like clothing and bedding, or by the respiratory droplets produced by sneezing or coughing, according to the W.H.O.That may sound eerily familiar because in the early days of the pandemic many experts said that the coronavirus also had little human-to-human transmission beyond respiratory droplets and contaminated surfaces. Later research showed that the coronavirus can spread through much smaller particles called aerosols with the ability to travel distances greater than six feet. But that doesn’t mean the same will turn out to be true for the monkeypox virus, said Luis Sigal, an expert in poxviruses at Thomas Jefferson University in Philadelphia. The coronavirus is a tiny, single-stranded RNA virus, which may have aided its ability to become airborne. The monkeypox virus, however, is made of double-stranded DNA, which means that the virus itself is much larger and heavier and unable to travel as far, Dr. Sigal said.Other routes of monkeypox transmission include from mother to fetus via the placenta or during close contact during and after birth.The majority of cases this year have been in young men, many of whom self-identified as men who have sex with men, though experts are cautious about suggesting that monkeypox transmission may occur through semen or other bodily fluids exchanged during sex. Instead, contact with infected lesions during sex may be a more plausible route. “This is not a gay disease, as some people in social media have attempted to label it,” Dr. Andy Seale, an adviser with the W.H.O.’s H.I.V., Hepatitis and S.T.I.s Program, said during Monday’s Q&A. “Anybody can contract monkeypox through close contact.”What are the symptoms and how bad can a monkeypox infection get?Monkeypox is part of the same family of viruses as smallpox, but it is typically a much more mild condition, according to the Centers for Disease Control and Prevention. On average, symptoms appear within six to 13 days of exposure, but can take up to three weeks. People who get sick commonly experience a fever, headache, back and muscle aches, swollen lymph nodes and general exhaustion.About one to three days after getting a fever, most people also develop a painful rash that is characteristic of poxviruses. It starts with flat red marks that become raised and filled with pus over the course of the next five to seven days. The rash can start on a patient’s face, hands, feet, the inside of their mouth or on their genitals, and progress to the rest of the body. (While chickenpox causes a similar-looking rash, it is not a true poxvirus, but is caused by the unrelated varicella-zoster virus).Once an individual’s pustules scab over, in two to four weeks, they are no longer infectious, said Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan in Canada.Children and people with underlying immune deficiencies may have more severe cases, but monkeypox is rarely fatal. While one strain found in Central Africa can kill up to 10 percent of infected individuals, estimates suggest that the version of the virus currently circulating has a fatality rate of less than 1 percent.And the easily identifiable rash of monkeypox, as well as its earlier symptoms, could be considered beneficial. “One of the most challenging things about Covid has been that it can be spread asymptomatically or pre-symptomatically, by people who have no idea that they’re infected,” Dr. Rasmussen said. “But with monkeypox it doesn’t appear that there is any pre-symptomatic transmission.”Still, as the recent outbreak of cases has shown, there are plenty of opportunities to transmit monkeypox in the first few days of an infection, when symptoms are non-specific, Dr. Rasmussen said.What to Know About the Monkeypox VirusCard 1 of 5What is monkeypox?