These are Insider's biggest healthcare stories for October 21. Hello,Welcome to Insider Healthcare. I'm healthcare editor Leah Rosenbaum, and today in healthcare news:The FDA authorized booster shots for the Moderna and Johnson & Johnson COVID-19 vaccines;Best Buy lays out its plan for entering the healthcare space;Dermatology startup Zerigo raised a $34 million Series B round to treat skin conditions with UV light.If you're new to this newsletter, sign up here. Comments, tips? Email me at lrosenbaum@insider.com or tweet @leah_rosenbaum. Let's get to it... An employee (R) of Japan's Suntory Holdings receives the Moderna coronavirus vaccine for Covid-19. KAZUHIRO NOGI/AFP via Getty Images The FDA just authorized booster shots of Moderna's and Johnson & Johnson's COVID-19 vaccines and is letting users mix and match shotsThe FDA authorized booster shots of the Moderna and J&J vaccines on Wednesday.The agency also authorized people to get different vaccine brand as a booster shot.J&J recipients can get a booster after two months. Moderna recipients should wait six months. Check it out>> Shoppers enter a Best Buy in New York. Associated Press/Bebeto Matthews A top Best Buy healthcare executive laid out how the retailer wants to help doctors care for patients in their homesBest Buy, known for selling electronics, is pushing deeper into healthcare.Best Buy Health President Deborah DiSanzo laid out its strategy at the HLTH conference in Boston.The retailer wants to help doctors care for patients at home through a new acquisition.Get the full story>> Zerigo makes a light-therapy device to treat skin conditions such as eczema. ipopba/Getty Images See the 17-slide presentation that convinced Livongo's Glen Tullman to invest in a dermatology treatment startupZerigo is a dermatology startup that treats conditions like psoriasis and eczema.It raised $43 million in Series B funding on Thursday led by Glen Tullman's 7wireVentures.Its smart device uses UVB light therapy to treat chronic dermatological conditions.See the slides now>>More stories we're reading:Pfizer says its booster shot has 95.6% efficacy against COVID-19 amid the Delta variant (Insider)A doctor developed a blood test for fibromyalgia. But did he tell the truth to his customers? (STAT)Blood tests that can detect cancer are about to hit the market. But experts are still waiting to see if they can upend deadly disease. (Insider)These doctors have been spreading COVID-19 vaccine misinformation for months (CNN)Pfizer's vaccine cuts the risk of COVID-19 hospitalization in teens by 93% in a CDC analysis (Insider)-LeahRead the original article on Business Insider.....»»