The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for Covid-19, the illness caused by the virus.

New York variant harbors a third worrisome mutation

The coronavirus variant on the rise in New York City contains the same E484K mutation seen in variants in Brazil and South Africa believed to make Covid-19 vaccines and antibody therapies less effective, as well as a mutation called S477N that helps it bind more tightly to cells when it breaks into them. A report by New York State Department of Health researchers posted on Monday on medRxiv ahead of peer review adds new information. All versions of the variant circulating in New York harbor a mutation called D235G that might reduce the efficacy of neutralizing antibodies. The variant "has increased in the circulating virus population in New York state by almost 26-fold in a little over a month," the researchers said. "The combination of E484K or S477N with a D253G mutation that might confer immune escape, and the increased number of Covid-19 cases associated with these variants, warrants further monitoring," they said.

Vaccinating the elderly preserves the most years of life

Prioritizing elderly people for Covid-19 vaccinations saves not only the most lives but also the most years of life, a new study suggests. Taking age and health risks into account, the authors calculated the number of lives potentially saved by Covid-19 vaccines in the United States, Germany and South Korea and multiplied that number by the life expectancy of those vaccinated. Patients' risk of death from Covid-19 rises faster with age - at a rate of about 11% per year - than their remaining life expectancy falls, said study leader Joshua Goldstein of the University of California, Berkeley. Without vaccinations, the numbers of people who would die of Covid-19 is so much higher in the oldest age groups than in younger groups that protecting the older groups actually saves more years of life, in total. "Before this study, it was suspected that there would be some intermediate age - not too old and not too young - which would maximize the benefit of a vaccine, in terms of person years of life saved," Goldstein said in a statement. Instead, vaccinating a 90-year-old in the United States would save twice as many years as vaccinating a 75-year-old, and six times as many as vaccinating a 50-year-old, his team reported on Thursday in the Proceedings of the National Academy of Sciences of the USA.

Full personal protective equipment can make wearers sick

Personal protective equipment (PPE) required in operating rooms and intensive care units can make wearers sick, a small study confirms. The findings help explain reports by clinicians of difficulty breathing, headache, and mental impairment while wearing the full protective suit that includes high quality mask, face shield and gloves, researchers said. Among the eight surgeons who volunteered for the study, PPE impaired breathing, resulting in high blood levels of carbon dioxide and low levels of oxygen. "Air re-breathed within the PPE mask after two hours was found to contain almost 8% carbon dioxide - 260-fold more than atmospheric levels (0.03%)," said Dr. Wyn Lewis of University Hospital of Wales in Cardiff. The changes were significantly greater than those seen with standard operating room garments, his team reported on Saturday in the British Journal of Surgery, and can cause fluctuations in brain blood flow, shortness of breath, sweating, dizziness, nausea, mental impairment, fatigue, and headache. Three of the surgeons experienced headaches related to altered blood flow in a major brain artery. "These findings were observed in young, fit, doctors, posing the question of what might emerge in mature professionals with co-existing medical issues, or anyone working beyond this study's two-hour limit," Lewis said.

Pandemic-waste plastics are threatening the planet

The Covid-19 pandemic has resulted in unmanageable levels of biomedical plastic wastes, researchers warn. Worldwide, approximately 3.4 billion single-use facemasks are generated and discarded daily. From those alone, the amount of pandemic-related plastic waste generated during the past year is equivalent to about 1.6 million tons per day, according to a report in the journal Heliyon. Plastic in masks, gloves, aprons, and bottles of sanitizers are overwhelming the capacity of waste management facilities worldwide, especially in developing nations, said study coauthor Nsikak Benson of Covenant University in Nigeria. Studies have shown that the new coronavirus can survive on plastic surfaces for days, but "the overwhelming nonexistence of effective waste management facilities in developing countries implies that a large percentage of single-use plastic waste generated might end up in open dump sites," Benson said. The report calls on governments and policy-makers to prioritize effective waste management of these contaminated plastics and to develop "robust" conservation strategies for sterilization and disinfection of surgical gowns and masks.