COVID-19 case count surpasses 350,000. As of March 23, 2020, the number of confirmed COVID-19 cases worldwide has exceeded 350,000, according to data from Johns Hopkins University. It took over three months to reach the first 100,000 confirmed cases of the virus, and only 12 days to reach the next 100,000. Four additional countries or territories in the Africa region reported cases between March 20 and March 21. Globally, the number of COVID-19 deaths is just over 15,000. [JHU, WHO]

Jump in Italy’s coronavirus death toll.In Italy, the death toll from coronavirus rose to 5,476, overtaking the current number of deaths reported in China and becoming the hardest hit country in the world. [JHU, Al Jazeera, Ministry of Health]

Countries shut borders, lockdown amid coronavirus pandemic. Countries and major cities around the world have imposed travel restrictions and locked down major cities to curb the spread of COVID-19. Over 50 countries have disallowed entry to non-citizen or non-resident travelers. On March 19, the US State Department issued a Level 4 “do not travel” advisory to American citizens encouraging their return to the US and to avoid all international travel. [NYT, US Department of State]

Researchers detail first known person-to-person transmission of COVID-19 in US.The first known person-to-person transmission of COVID-19 in the US occurred between an infected woman in her 60s who returned from China in mid-January and her husband who did not travel but had prolonged and unprotected close contact with his wife. An additional 372 people who had contact with the woman and her husband were identified, 347 of those underwent active symptom monitoring and 43 were placed under investigation. All contacts tested negative for the virus.[The Lancet]

Temperature and humidity may reduce COVID-19 transmission.High temperature and high humidity may reduce the transmission of COVID-19, according to an analysis of 100 Chinese cities with more than 40 cases. [SSRN]

First US company offers at-home COVID-19 test.Everlywell, a US-based company offering at-home lab testing kits, will launch a COVID-19 test that will be available to consumers beginning March 23. The company is the first in the US to launch an at-home test following the Food and Drug Administration’s February announcement allowing laboratories that are certified to perform high-complexity testing to develop and distribute tests. The US FDA recently expanded its policy easement to include commercial manufacturers. Companies developing and releasing COVID-19 tests will not be required to purse Emergency Use Authorization with the agency. The FDA has also charged individual states with overseeing the development and use of new diagnostic tests. [TIME, FDA, FDA Statement]

Multistate Listeria outbreak kills four people. The Centers for Disease Control and Prevention (CDC) announced that an outbreak of Listeria monocytogenes has infected 36 people across 17 US states and killed four in California, Hawaii, and New Jersey. Evidence suggests that Enoki mushrooms sold by Sun Hong Foods and labeled, “Product of Korea” is the likely source of the outbreak. [CDC]

Antibiotic use variability in US pediatric hospitals. More than a third of hospitalized children at 51 US hospitals received an antibiotic on any given day, and 1 in 8 received a broad-spectrum antibiotic, according to four single-day point prevalence surveys which reviewed antibiotic prescribing and consumption for over 50,000 pediatric patients. The prevalence of antibiotic use varied from 22.3 percent to 51.9 percent across all facilities and clinical settings. Pediatric intensive care units had the highest prevalence of overall and broad-spectrum antibiotic use at prevalence rates of 58.3 and 26.6 percent, respectively. [Infection Control and Hospital Epidemiology]

Three-drug antimalarial regimen effective in high resistance settings. Adding mefloquine or amodiaquine to existing two-drug artemisinin-based combination therapies (ACTs) is effective in treating malaria even in high-resistance settings, according to a randomized trial involving 1,100 patients across 18 health facilities in eight countries. Patients received treatments with either dihydroartemisinin–piperaquine plus mefloquine or artemether–lumefantrine plus amodiaquine. 42-day corrected efficacy rates of dihydroartemisinin–piperaquine plus mefloquine was significantly higher than treatment without mefloquine (97 versus 60 percent). The triple combination therapy also resulted in significantly less reoccurring infections in countries with a high prevalence of artemisinin-resistant parasites. [The Lancet]

Varying flu vaccine effectiveness in Europe. During the 2019/2020 influenza season, influenza A accounted for 84 percent of laboratory-confirmed cases across 10 European countries and 16 percent were from influenza B. Vaccine effectiveness (VE) against laboratory-confirmed influenza A and B ranged from 29 to 61 percent in four primary care settings in Denmark, Spain, and the UK. In hospital settings, VE was 40 percent among patients of all ages and ranged from 35 to 60 percent in patients over 65 years. [Eurosurveillance]

Flu surveillance case definitions miss older adults. Hospitalized older adults are less likely to meeting existing influenza-like illness (ILI) and severe acute respiratory illness (SARI) case definitions, according to a prospective cohort study in Canada. During the 2011/12, 2012/13, and 2013/14 influenza seasons, there were 4,942 laboratory-confirmed influenza cases among the 11,379 patients included in the study. The median age of included patients was 72 years. Only 44.6 percent of older patients with confirmed influenza met ILI criteria compared to 51.1 percent of younger patients. Overall, 57.1 percent of older patients met SARI criteria compared to 64.1 percent of younger patients. Older patients who were frail or pre-frail were less likely to meet ILI or SARI criteria. [Infection Control and Hospital Epidemiology]