MMWR News Synopsis

Friday, July 23, 2021


Changes in Influenza and Other Respiratory Viral Activity During the COVID-19 Pandemic — United States, 2020–2021

CDC Media Relations

CDC researchers analyzed the circulation of respiratory viruses during the COVID-19 pandemic, including influenza viruses, respiratory syncytial virus (RSV), the four common human coronavirus types other than SARS-CoV-2 (the virus that causes COVID-19), parainfluenza viruses, human metapneumoviruses, respiratory adenoviruses, and rhinoviruses/enteroviruses. In 2020, most of these viruses circulated at historically low levels, likely because of widespread use of COVID-19 prevention measures, including limited global travel, mask use,  physical distancing, and staying home. However, some of these viruses, such as RSV, have begun circulating at increased levels at an unusual time of the year. As COVID-19 prevention practices are relaxed, CDC expects the spread of respiratory viruses could increase. The lack of natural exposure to influenza, RSV, and other respiratory viruses during 2020 may have reduced population immunity to these viruses, especially among younger children. This lack of immunity might lead to more widespread disease and potentially more severe epidemics as respiratory viruses resume circulation at pre-pandemic levels. Clinicians and public health professionals should be aware of current increases in RSV activity and anticipate that circulation of other respiratory viruses, including influenza, may resume. Influenza vaccination and use of everyday preventive actions such as avoiding close contact with people who are sick, staying home when sick, covering coughs and sneezes, and frequent handwashing, will be important to prevent infection with influenza and other respiratory viruses.

Heat-Related Emergency Department Visits During the Northwestern Heat Wave — United States, June 2021 (Early Release July 16, 2021)

CDC Media Relations

Notes from the Field

Candida auris (C. auris) is an emerging, often multidrug-resistant yeast that spreads easily and results in outbreaks in health care settings. Most invasive C. auris infections should be treated with a class of antifungal drugs called echinocandins. During January–April 2021, two independent clusters of pan-resistant (resistance to all three classes of antifungal drugs available for treating infections) or echinocandin-resistant cases of C. auris were detected in U.S. health care facilities. This is the first evidence suggesting spread of pan-resistant strains of C. auris in the U.S. While C. auris is much more resistant to antifungal medications than other similar fungal diseases, reports of resistance to all three classes of antifungal drugs have been rare in the United States. Among 101 cases in Washington, D.C. during January–April 2021, three pan-resistant cases were identified at a long-term care facility. Among 22 cases in Texas during January–April 2021, two were pan-resistant and five were resistant to both echinocandins and fluconazole, another antifungal medication. These clusters are the first evidence suggesting spread of echinocandin- and pan-resistant strains of C. auris in the U.S. rather than development of resistance in patients during antifungal treatment. Early identification through screening and testing, rigorous infection control, and coordinated communication are essential to prevent the spread of C. auris, particularly pan-resistant and echinocandin-resistant strains. Testing for drug resistance is critical to prevent spread.

Recommendations and Reports

CDC releases updated sexually transmitted infections treatment guidelines as chlamydia, gonorrhea, and syphilis cases continue to increase. These guidelines provide current evidence-based diagnostic, management, and treatment recommendations, and serve as a source of clinical guidance for managing sexually transmitted infections. Notable updates to the previous 2015 guidance include:

  • Updated treatment recommendations for chlamydia, trichomoniasis, and pelvic inflammatory disease.
  • Updated treatment recommendations for uncomplicated gonorrhea in neonates, children, and other specific clinical situations (e.g., proctitis, epididymitis, sexual assault).
  • Information on FDA-cleared diagnostic tests for Mycoplasma genitalium and rectal and pharyngeal chlamydia and gonorrhea.
  • Expanded risk factors for syphilis testing among pregnant women.
  • Recommended two-step serologic testing for diagnosing genital herpes simplex virus.
  • Aligned recommendations for human papillomavirus (HPV) vaccination with the Advisory Committee on Immunization Practices.
  • Recommended universal hepatitis C testing in alignment with CDC’s 2020 hepatitis C testing recommendations.



CDC works 24/7 protecting America’s health, safety and security. Whether diseases start at home or abroad, are curable or preventable, chronic or acute, or from human activity or deliberate attack, CDC responds to America’s most pressing health threats. CDC is headquartered in Atlanta and has experts located throughout the United States and the world.

Page last reviewed: July 21, 2021