The virus is evolving, and the newest version spreads more often through heterosexual populations. But the vaccines should still work.Faced once again with a rapidly spreading epidemic of mpox, the World Health Organization on Wednesday declared a global health emergency. The last time the W.H.O. made that call was in 2022, when the disease was still called monkeypox.Ultimately the outbreak affected nearly 100,000 people worldwide, primarily gay and bisexual men, including more than 32,000 in the United States.The W.H.O.’s decision this time was prompted by an escalating crisis of mpox concentrated in the Democratic Republic of Congo. It recently spread to a dozen other African countries. If it is not contained, the virus again may rampage all over the world, experts warned.“There’s a need for concerted effort by all stakeholders, not only in Africa, but everywhere else,” Dr. Dimie Ogoina, a Nigerian scientist and chair of the W.H.O.’s mpox emergency committee, said on Wednesday.Congo alone has reported 15,600 mpox cases and 537 deaths, most of them among children under 15, indicating that the nature of the disease and its mode of spread may have changed.Here’s what to know.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

The epidemic is concentrated in the Democratic Republic of Congo, but the virus has now appeared in a dozen other African countries.The rapid spread of mpox, formerly called monkeypox, in African countries constitutes a global health emergency, the World Health Organization declared on Wednesday.This is the second time in three years that the W.H.O. has designated an mpox epidemic as a global emergency. It previously did so in July 2022. That outbreak went on to affect nearly 100,000 people, primarily gay and bisexual men, in 116 countries, and killed about 200 people.The threat this time is deadlier. Since the beginning of this year, the Democratic Republic of Congo alone has reported more than 14,000 mpox cases and 524 deaths. Those most at risk include women and children under 15.“The detection and rapid spread of a new clade of mpox in eastern D.R.C., its detection in neighboring countries that had not previously reported mpox, and the potential for further spread within Africa and beyond is very worrying,” said Dr. Tedros Adhanom Ghebreyesus, the W.H.O.’s director general.The outbreak has spread through 13 countries in Africa, including a few that had never reported mpox cases before. On Tuesday, the Africa Centers for Disease Control and Prevention declared a “public health emergency of continental security,” the first time the organization has taken that step since the African Union granted it the power to do so last year.“It’s in the interests of the countries, of the continent and of the world to get our arms around us and stop transmission as soon as we can,” said Dr. Nicole Lurie, the executive director for preparedness and response at the Coalition for Epidemic Preparedness Innovations, a nonprofit that finances vaccine development.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

The sometimes fatal condition, MIS-C, may be driven in part by a misdirected immune system, a new study finds.When exposed to a virus, the human body marshals the immune system to fend off the intruder. Sometimes, the defense goes awry, and the body mistakenly turns against itself instead of the attacker.This sort of friendly fire drives multi-inflammatory syndrome in children, or MIS-C, a mysterious condition that in rare cases strikes children who have had a severe bout of Covid-19, according to a new study.In a subset of children with the syndrome, immune cells become confused by the similarity between a protein carried by the coronavirus and one found throughout the human body, said Joseph DeRisi, an infectious disease expert and the president of the Chan Zuckerberg Biohub in San Francisco, who led the study. This phenomenon is called molecular mimicry, Dr. DeRisi said.The study was published on Wednesday in the journal Nature. The results offer the first direct proof that Covid-19 sets off an autoimmune reaction that leads to MIS-C.“This adds a very clear layer of evidence that there is an autoimmune component to MIS-C,” said Dusan Bogunovic, a pediatric immunologist at Columbia University who was not involved in the work.Scientists have long known that infections can befuddle the body into attacking itself, but the new study is among the first to identify the series of events and cast of immune characters involved in the process.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

A common antibiotic, doxycycline, greatly reduced cases of syphilis, gonorrhea and chlamydia when taken every day, a study found.A daily dose of a widely used antibiotic can prevent some infections with syphilis, gonorrhea and chlamydia, potentially a new solution to the escalating crisis of sexually transmitted infections, scientists reported on Thursday.Their study was small and must be confirmed by more research. Scientists still have to resolve significant questions, including whether S.T.I.s might become resistant to the antibiotic and what effect it could have on healthy gut bacteria in people taking it every day.The approach would be recommended primarily to people at elevated risk of sexually transmitted infections during certain periods, said Dr. Jeffrey Klausner, an infectious diseases physician at the University of Southern California who was not involved in the new work.“The number of people who are really going to be offered this and take this is still very small,” he said. “In general, the more choices we have for people, the more prevention options we have, the better.”The results will be presented next week at a conference of the International AIDS Society in Munich.The United States now has the highest rate of new syphilis infections since 1950, the Centers for Disease Control and Prevention reported in January. In 2022, the last year for which data are available, there were 1.6 million cases of chlamydia and nearly 650,000 new cases of gonorrhea.Previous studies have shown that the antibiotic doxycycline substantially cuts the risk of new infections if taken within 72 hours after unprotected sex. The C.D.C. now recommends taking doxycycline after “oral, vaginal or anal sex.”We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

A new study adds to evidence that the shots can reduce the chances of developing one of the most dreaded consequences of Covid.A summer wave of Covid is surging in many parts of the nation. Infections, emergency room visits and hospitalizations are all on the upswing.Recognizing that Covid is now a permanent respiratory threat, as are influenza and respiratory syncytial virus, federal officials have recommended that everyone 6 months and older receive the newest vaccine this fall.If last year is any indication, many Americans may pay no heed, opting instead to take their chances with another bout. Nearly everyone has layers of immunity acquired from prior illnesses and immunizations. For many, another go-round with Covid just means a few days of misery.But for some people with certain risk factors — age, pregnancy, chronic conditions or a compromised immune system — an infection may bring serious illness. “It’s very, very important that they get vaccinated,” said Dr. Ziyad Al-Aly, the chief of research and development at the V.A. St. Louis Health Care System.In every age group, even a mild illness may trigger a lasting set of problems. Nearly 14 million Americans, or about 5.3 percent of adults, may now be living with long Covid, according to the Centers for Disease Control and Prevention. A study published on Wednesday offers strong evidence that vaccination reduces the odds of getting long Covid.“It’s very clear that no demographic group is spared,” Dr. Al-Aly said. Does Covid still matter?Yes. This summer’s wave is a sign that Covid remains a problem. By nearly every measure, infections are on the rise.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

Even as the H5N1 virus evolves, gaps remain in the nation’s contingency plans for human testing, scientists say.The first step in combating any infectious disease outbreak is detection. Without widespread testing, health officials have little sense of who is infected, when to treat patients and how to monitor their close contacts.In that sense, the bird flu outbreak plaguing the nation’s dairy farms is spreading virtually unobserved.As of Monday, the virus had infected 157 herds in 13 states. But while officials have tested thousands of cows and are monitoring hundreds of farmworkers, only about 60 people have been tested for bird flu.Officials do not have the authority to compel workers to get tested, and there is no way for workers to test themselves. In the current outbreak, just four dairy workers and five poultry workers have tested positive for H5N1, the bird flu virus, but experts believe that many more have been infected.The Covid-19 pandemic and the mpox (formerly monkeypox) outbreak in 2022 revealed deep fissures in the U.S. approach to testing for emerging pathogens. Those failures prompted federal agencies to move toward policies that would allow rapid scaling of testing during an outbreak.But progress has been sluggish, interviews with more than a dozen academic and government experts suggest.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

Hoau-Yan Wang, a professor at City College, published studies supporting simufilam, now in advanced clinical trials.A scientist whose research has been at the center of controversy over an Alzheimer’s drug candidate has been charged with fraud.A federal grand jury on Thursday indicted Hoau-Yan Wang, a professor at the City College of New York, on charges of falsifying data to obtain grants totaling roughly $16 million from the National Institutes of Health.Dr. Wang’s studies underpinned research into a diagnostic test for Alzheimer’s disease and simufilam, a drug in advanced clinical trials. Simufilam’s manufacturer, Cassava Sciences, a pharmaceutical company based in Texas, has said the drug improves cognition in Alzheimer’s patients.Alzheimer’s disease affects roughly six million Americans — a number that is expected to double by 2050 — and promising treatments generate tremendous excitement. Cassava’s stock soared after each round of reported results from its trials.But some scientists had publicly disparaged the drug, saying its mechanism of action and purported results were implausible. Some went further and accused the company and Dr. Wang, its scientific consultant, of manipulating results. Several journals retracted or attached statements of concern to publications by Dr. Wang and a co-author at Cassava.Hoau-Yan WangAfter the indictment was announced on Friday, Cassava’s stock plummeted to its lowest price since October 2020.Remi Barbier, the founder and chief executive of Cassava, did not immediately respond to a request for comment. But in a statement posted on its website, the company said Dr. Wang’s work “was related to the early development phases of the company’s drug candidate and diagnostic test.”“Dr. Wang and his former public university medical school have had no involvement in the company’s Phase 3 clinical trials of simufilam,” the statement said.A publicist for the company pointed to a September 2023 publication that he said provides “independent verification of the science.”An investigation by the City University of New York, of which the college is a part, struggled for months to obtain access to Dr. Wang’s files. Eventually, members of the investigating committee concluded that Dr. Wang had been “reckless” in his failure to keep or provide original data, an offense that “amounts to significant research misconduct.”Neither the college nor Dr. Wang immediately responded to requests for comment on the indictment.Dr. Wang is now accused of falsifying data in grant applications over nearly eight years ending in April 2023, according to the Justice Department. Some of the grants funded Dr. Wang’s salary and laboratory research at the university.Federal prosecutors charged Dr. Wang with multiple counts of fraud and false statements. If convicted, he faces a maximum prison sentence of 55 years.The Federal Bureau of Investigation’s Washington field office is investigating the case. The indictment was handed down in Maryland, where the N.I.H. is based.In an emailed statement, Renate Myles, a spokeswoman for the N.I.H., said the agency “does not discuss grants compliance reviews on specific funded awards, recipient institutions or supported investigators.”“However, N.I.H. takes research misconduct very seriously,” she said. “N.I.H. promptly and carefully reviews all allegations of research misconduct received.”

As the virus continues to mutate, scientific advisers to the C.D.C. are urging Americans to roll up their sleeves again for annual vaccinations.All Americans ages 6 months and older should receive one of the new Covid-19 vaccines when they become available this fall, scientific advisers to the Centers for Disease Control and Prevention said on Thursday.The recommendation comes as the nation faces a summer wave of Covid, with the number of infections rising in at least 39 states and territories.Most Americans have acquired layers of immunity against the coronavirus from repeat infections or vaccine doses, or both. The vaccines now offer an incremental boost, remaining effective for only a few months as immunity wanes and the virus continues to evolve.Still, across every age group, a vast majority of Americans who were hospitalized for Covid did not receive one of the shots offered last fall, according to data presented at a meeting of the C.D.C.’s Advisory Committee on Immunization Practices.“Professionals and the public in general do not understand how much this virus has mutated,” said Carol Hayes, the committee’s liaison to the American College of Nurse-Midwives. “You need this year’s vaccine to be protected against this year’s strain of the virus.”A vaccine by Novavax will target JN.1, the variant that prevailed for months in the winter and spring. The shots to be made by Pfizer and Moderna are aimed at KP.2, which until recently seemed poised to be the dominant variant.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

Fewer Americans age 60 to 74 should receive the shots, the agency concluded, citing reduced risks and a possible neurological side effect.In an unusual move, federal health officials narrowed their recommendations for who should receive the vaccine against the respiratory syncytial virus.The Centers for Disease Control and Prevention advised last year that adults age 60 or older could receive a single lifetime dose of an R.S.V. vaccine, in consultation with their health care providers.On Wednesday, scientific advisers to the agency reframed that guideline. Based on recent safety and effectiveness data, they unanimously recommended that all Americans age 75 and older receive one dose of an R.S.V. vaccine.But for adults 60 to 74 years of age, the panel endorsed vaccination only for those with certain serious conditions, such as chronic heart or lung disease, advanced kidney disease and diabetes with organ damage.The advisers voted not to recommend the vaccine for other adults in this age group, although individuals may still consult with their health care providers to evaluate the risk the infection poses to them.The C.D.C.’s director, Dr. Mandy Cohen, accepted the panel’s recommendations on Wednesday afternoon.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

There is no guarantee that a person-to-person virus would be benign, scientists say, and vaccines and treatments at hand may not be sufficient.The bird flu outbreak in dairy cattle has so far spilled over to just three farmworkers in the United States, as far as public health authorities know. All of them have had mostly mild symptoms.But that does not guarantee that the virus, called H5N1, will remain benign if it begins to spread among people. Accumulating evidence from the animal world and data from other parts of the globe, in fact, suggest the opposite.Some dairy cows never recovered from H5N1, and died or were slaughtered because of it. Infected terns seemed disoriented and unable to fly. Elephant seal pups had trouble breathing and developed tremors after catching the virus. Infected cats went blind, walking in circles; two-thirds of them died.“I definitely don’t think there is room for complacency here,” said Anice Lowen, a virologist at Emory University.“H5N1 is a highly pathogenic type of influenza virus, and we need to have a high degree of concern around it if it’s spilling over into humans,” she said.In ferrets experimentally inoculated with the virus through their eyes — the presumed route of infection in the U.S. farmworkers — the virus rapidly spread to their airways, lungs, stomach and brain, according to a report published on Wednesday.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.