More than 700,000 Americans may have lost their sense of smell after developing Covid-19, the World Health Organization (WHO) plans to draft an international accord to prevent future pandemics, and more—in this week's roundup of Covid-19 news.

• GlaxoSmithKline (GSK) and Vir Biotechnology last week announced that early laboratory studies suggest their Covid-19 antibody treatment, sotrovimab, is effective against the omicron variant, the Wall Street Journal reports. According to the companies, the preliminary findings are based on tests of the treatment against individual mutations found in the omicron variant. To confirm the initial results, the companies plan to test the treatment against omicron's mutated spike protein, instead of just individual mutations. Amanda Peppercorn, who leads Covid-19 monoclonal antibody development at GSK, said she expects the results of the spike protein testing within the next two to three weeks. According to the Journal, the United States in November purchased an additional 300,000 doses of GSK and Vir's antibody treatment before omicron was discovered. (Roland, Wall Street Journal, 12/2; Roland, Wall Street Journal, 11/17)

• Ursula von der Leyen, president of the European Commission, on Wednesday said the 27 member nations should consider mandating Covid-19 vaccines for their citizens, the Associated Press reports. "It is understandable and appropriate to lead this discussion now—how we can encourage and potentially think about mandatory vaccination within the European Union," von der Leyen said. Currently, around a third of the European population, or around 150 million people, remain unvaccinated. "The lifesaving vaccines are not being used adequately everywhere," von der Leyen said. So far, a few European countries have already announced their own plans to mandate Covid-19 vaccines. For example, Austria will begin mandating vaccines for all residents beginning Feb. 1, and Greece in mid-January will begin fining people ages 60 and up 100 euros a month if they are not vaccinated, AP reports. (Casesrt, Associated Press, 12/1; Oshin, The Hill, 12/1)

• WHO on Wednesday voted to draft a "convention, agreement, or other international instrument" aimed at preventing, preparing for, and responding to future pandemics, NPR reports. According to WHO Director-General Tedros Adhanom Ghebreyesus, the international treaty is intended to avoid the "fragmented and splintered" steps that weakened the global response to Covid-19. Some components of the treaty could include commitments to share data, virus samples, and technology, as well as to ensure vaccine equity, the New York Times reports. "The adoption of this decision is cause for celebration, and cause for hope, which we will need," Tedros said. "There are still differences of opinion about what a new accord could or should contain. But you have proven to each other and the world that differences can be overcome, and common ground can be found." According to NPR, the intergovernmental negotiating body will meet by March 1 to begin drafting the new accord, which is expected to be completed by 2024. (Hernandez, NPR, 12/1; Cumming-Bruce, New York Times, 12/1)

• A study published in JAMA Otolaryngology found that more than 700,000 Americans may have already experienced chronic loss of smell after developing Covid-19. For the study, researchers used national data on new daily Covid-19 cases and studies on the incidence of acute olfactory dysfunction and recovery rates to estimate the number of people in the United States who have lost the ability to smell. They found that estimates ranged from a low of 170,238 to a high of 1.6 million people, with intermediate estimates suggesting that more than 700,000 people had developed long-term olfactory problems by August. According to the researchers, widespread loss of smell could have significant effects on public health, potentially decreasing people's quality of life and limiting their ability to detect harmful gas and smoke. Researchers wrote that the data "suggest[s] an emerging public health concern of [olfactory dysfunction] and the urgent need for research that focuses on treating Covid-19 [chronic olfactory dysfunction]." (Carbajal, Becker's Hospital Review, 11/19)

• A study published in Science found that SARS-CoV-2 antibody levels were associated with Covid-19 vaccine efficacy, with higher levels correlating with greater protection. For the study, researchers at Fred Hutchinson Cancer Research Center evaluated 30,420 adults who received Moderna's Covid-19 vaccine at 99 centers. Study participants were assessed for neutralizing antibodies as correlates of risk and protection against coronavirus infection. The researchers measured antibody levels at an individual's second vaccine dose and then again four weeks later. They found that antibody concentrations were directly correlated to vaccine efficacy and inversely associated with infection risk. In particular, recipients with 50% neutralizing antibody levels with 10, 100, and 1,000 international units per milliliter had vaccine efficacies of 78%, 91%, and 96%, respectively. According to the researchers, these results help define immune markers as correlates of protection, which can measure how much immunity is needed to prevent infection from the coronavirus. Identifying correlates of protection against Covid-19 could expedite vaccine research and regulatory approval for existing vaccines. "Our findings that all evaluated binding and neutralizing antibody markers strongly inversely correlated with Covid-19 risk, and directly correlated with vaccine efficacy, adds evidence toward establishing an immune marker surrogate endpoint for mRNA Covid-19 vaccines," the researchers wrote. (Gilbert et al., Science, 11/23; University of Minnesota Covid-19 Scan, 11/24)