The delta variant now makes up more than 99% of Covid-19 cases in the United States, daily Covid-19 deaths are the highest they've been since early March, and more in this week's roundup of Covid-19 news.

• A study published in the Annals of Internal Medicine suggests that the pandemic cut U.S. life expectancy by more than 9 million cumulative years, Axios reports. For the study, researchers used data from the Health and Retirement Study, the Panel Study of Income Dynamics, CDC, and CMS to create a model measuring years of life and quality-adjusted life years lost from the pandemic by age, sex, race/ethnicity, and comorbidity. The researchers found each person who died from Covid-19 lost an average of 12 years of life, and over a third of those who died would have likely either had a normal or better than normal life expectancy. Of the 9 million years of lost life expectancy, 4.7 million were lost by adults ages 25 to 64. In addition, Black and Hispanic Americans were most impacted by the reduced life expectancy, losing more than twice as many years per capita than white Americans. (Fernandez, Axios, 9/21; Commins, HealthLeaders Media, 9/20)

• President Joe Biden on Wednesday hosted a virtual global vaccine summit where he announced new goals for global vaccination, including vaccinating 70% of the world's population by next September. According to the New York Times, the Biden administration plans to donate an additional 500 million doses of the Pfizer-BioNTech vaccine to other countries and $370 million to administer the shots. In addition, Vice President Kamala Harris announced the United States would donate $250 million to a new global health security fund that will be used to fight future pandemics. However, several leaders, including South African President Cyril Ramaphosa and Indian Prime Minister Narendra Modi, pressed back on Biden's plan, saying more should be done by "better-resourced nations." In particular, the leaders said intellectual property waivers should be applied to the Covid-19 vaccines so that they can be manufactured directly in other countries. According to the Times, the United States has been in talks with both Moderna and Pfizer to license their vaccine formulas and technologies to manufacturers overseas, although no licensing agreements have been reached. (Stolberg, New York Times, 9/22 [1]; Gonzalez, Axios, 9/22; Lesniewski, Roll Call, 9/22; Levin/Peltier, New York Times, 9/22; Stolberg, New York Times, 9/22 [2]; Nolen/Stolberg, New York Times, 9/22; Baker, STAT News, 9/22; Mueller, New York Times, 9/22)

• A clinical trial of Gilead's Covid-19 drug remdesivir found that administering the drug within a week of symptom onset reduced patients' risk of hospitalization by 87% and reduced medical visits by 81%, the company said on Wednesday. The study involved 562 patients who were age 60 or older or had at least one risk factor for severe Covid-19. All patients had been diagnosed with Covid-19 within four days of treatment and had experienced symptoms for a week or less. Currently, remdesivir, which Gilead has branded Veklury, is the only Covid-19 treatment that has received full FDA approval, STAT News reports. (Herper, STAT News, 9/22; Anderson, Becker's Hospital Review, 9/22)

• The delta variant now makes up more than 99% of coronavirus cases tracked in the United States, according to CDC data. Delta, which initially made up just over 25% of cases in mid-June, has since become the dominant variant of the virus in the country, the New York Times reports. In addition, Maria Van Kerkhove, a scientist at the World Health Organization (WHO), on Tuesday said the delta variant has become "predominant worldwide." Other WHO variants of concern, such has alpha, beta, and gamma, now make up less than 1% of coronavirus sequences shared globally, she said. According to Kerkhove, delta is "by far" the most transmissible variant of the coronavirus and has been reported in more than 185 countries. (Ramos, New York Times, 9/20; Schnell, The Hill, 9/22)

• The Asthma and Allergy Foundation of America (AAFA) on Tuesday warned against inhaling hydrogen peroxide through a nebulizer to prevent or treat Covid-19, The Hill reports. In a blog post, AAFA said the treatment, which has gained popularity on social media in recent weeks, is "concerning and dangerous." Although hydrogen peroxide is often used to treat minor cuts and burns, it can be toxic if ingested or inhaled, potentially leading to respiratory or severe pulmonary irritation, according to the Agency for Toxic Substances and Disease Registry. "Only use asthma medicine prescribed by your doctor in your nebulizer. Other chemicals can be harmful to your lungs," AAFA said. (Beals, The Hill, 9/22; Mendoza, USA Today, 9/22)

• The United States is now averaging more than 1,900 daily Covid-19 deaths, according to data from Johns Hopkins University (JHU)—the highest level the country has seen since early March. In addition, JHU data shows the United States has surpassed more than 676,000 deaths from Covid-19. According to Axios, this means the Covid-19 pandemic has now killed more Americans than the 1918 flu pandemic—though the proportion of deaths due to the 1918 flu was larger due to the country's smaller population size at the time. While the 1918 flu pandemic killed around one in 150 Americans, the Covid-19 pandemic has so far killed more than one in 500 Americans, Axios reports. (Saric, Axios, 9/21; AP/Modern Healthcare, 9/20; AP/Modern Healthcare, 9/21; Schnell, The Hill, 9/22)