One-shot wonders

Covid's comeback is bigger but less deadly, at least for now Trump to resume public events starting Saturday at White House Hurdles to U.S. stimulus climb after Trump's abrupt tactical shift One-shot wonders The first round of Covid-19 vaccines may reach the U.S. before year-end, but getting them widely distributed to an entire country will be no easy feat. The leading vaccine candidates from Pfizer Inc. and partner BioNTech SE as well as Moderna Inc. face a number of hurdles. Both inoculations use a relatively new technology, engineered messenger RNA, that so far has needed a follow-up booster shot to make the vaccinations effective. Aside from needing to produce twice the number of doses to immunize a population, getting Americans to follow up with their health-care provider on a two-shot regimen will also be tricky. One under-the-radar company, Arcturus Therapeutics Holdings Inc., thinks it may have the solution: self-replicating messenger-RNA that may need only a single, low-dose shot to spur on an immune response. Hit me with your best shot: Can a single, low-dose inoculation spur an immune response? Photographer: Marco Bello/Bloomberg ARCT-021 uses Arcturus's proprietary technology to deliver a self-amplifying RNA payload directly into cells. That drives the production of antigens, the proteins that spur an immune response, which are produced over a two-to-three-week period instead of the two-to-three days seen with leading mRNA vaccines. The hope is that a single shot will be more active at much lower doses. The Arcturus vaccine candidate may address another logistical nightmare for mRNA, the need for refrigeration at extreme sub-freezing temperatures. ARCT-021 will be lyophilized, or freeze-dried, so it's believed that it can be stored at normal refrigerator temperatures. The company should have its first look at data in human volunteers in the current quarter. Of course Arcturus isn't the only one chasing the one-shot dream. Johnson & Johnson is furthest along for a single treatment vaccine after starting a 60,000-person study in September and could be among the first wave of companies to win an emergency-use authorization. In August, Merck & Co. started clinical testing of a vaccine based around the technology used against measles.—Cristin Flanagan Listen up The Risk to Overweight People Obesity is a known risk factor for severe complications of Covid-19. But scientists are learning that the link between extra pounds and severe Covid-19 may be even stronger than they thought. This week, the U.S. Centers for Disease Control and Prevention said that people who are merely overweight, not just the obese, may be at high risk of serious disease from the infection. Photographer: Patricia Suzara Photographer: Patricia Suzara   What you should read Robinhood Users Say Accounts Were Looted Platform told users they'd respond to complaints within "a few weeks." The TikTok Party House Next Door Young influencers have turned mansions into nightclubs during pandemic. Luxury Thai Hotels Betting on 5-Star Quarantine A slew of new hotels is counting on plan to attract high-spending tourists. Virus May Bring Germany a Canine Cash Windfall A jump in dog ownerships during pandemic may fuel tax revenue. Covid Tests Come Quickly in U.K., If You Can Pay The U.K. has Europe's highest death toll and still struggles with testing. Know someone else who would like this newsletter?  Have them sign up here. Have any questions, concerns, or news tips on Covid-19 news? Get in touch or help us cover the story. Like this newsletter? Subscribe for unlimited access to trusted, data-based journalism in 120 countries around the world and gain expert analysis from exclusive daily newsletters, The Bloomberg Open and The Bloomberg Close. Follow Us Get the newsletter You received this message because you are subscribed to Bloomberg's Coronavirus Daily newsletter. Unsubscribe | Bloomberg.com | Contact Us Bloomberg L.P. 731 Lexington, New York, NY, 10022