MMWR News Synopsis

Articles

Interim Estimates of 2021–22 Seasonal Influenza Vaccine Effectiveness — United States, February 2022

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Preliminary flu vaccine effectiveness estimates for the 2021–2022 flu season suggest flu vaccination did not reduce the risk of mild or moderate influenza caused by the H3N2 flu virus, which has been the most common strain this season. Studies are ongoing to determine how well the flu vaccine protected against severe flu outcomes this season. There is a growing body of research suggesting vaccination can prevent serious outcomes even when it does not prevent infection. Flu activity so far this season has been lower than in flu seasons before the COVID-19 pandemic. Limited influenza circulation this season made it challenging to evaluate vaccine effectiveness, but preliminary vaccine effectiveness results from CDC’s U.S. Flu Vaccine Effectiveness Network indicate that vaccination did not reduce the risk of mild or moderate illness from H3N2 viruses, which circulated most commonly this season. Final data will be available later this year. These findings are consistent with findings from a rapid, early-season CDC field study, which showed that vaccination provided no measurable protection against mild illness caused by H3N2 viruses in an influenza outbreak on a university campus. Ongoing studies are evaluating whether vaccination this season provided some protection against more severe illness and hospitalizations. There is a growing body of evidence, particularly among young children who are at increased risk for severe complications, suggesting that influenza vaccination can reduce the severity of illness, even among people who get vaccinated and still get sick with flu. CDC continues to recommend flu vaccination as long as flu activity is ongoing. Significant flu activity can happen into May with different flu viruses circulating at different times, and flu vaccines protect against four different flu viruses.

Characteristics and Adverse Events of Patients for Whom Nifurtimox Was Released Through CDC-Sponsored Investigational New Drug Program for Treatment of Chagas Disease — United States, 2001–2021

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The FDA approval and commercial availability of nifurtimox as Lampit^® (Bayer) are anticipated to improve access to therapy for the more than 300,000 estimated people with Chagas disease living in the United States. Providers should be aware of the frequency and types of adverse events when counseling patients and prescribing nifurtimox. Nifurtimox is used to treat Chagas disease, or American trypanosomiasis, which is caused by the parasite Trypanosoma cruzi. The parasite is primarily transmitted by triatomine insects, or kissing bugs, and also from mother to unborn child. Chagas disease is endemic in rural areas of Latin America; however, transmission can occur in the United States. Nifurtimox (Lampit^®) was exclusively available through CDC under an Institutional Review Board-approved Investigational New Drug treatment protocol before the drug became commercially available in January 2021. Adverse events were frequently reported by patients receiving the medication, although most were mild. FDA approval and commercial availability of Chagas treatments are anticipated to improve access to therapy for the more than 300,000 estimated people with T. cruzi infection living in the United States.

Evaluation of Serologic Cross-Reactivity Between Dengue Virus and SARS-CoV-2 in Patients with Acute Febrile Illness — Puerto Rico, April 2020–March 2021

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COVID-19 Vaccine Provider Access and Vaccination Coverage Among Children Aged 5–11 years — United States, November 2021–January 2022

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Successful vaccination coverage requires thoughtful planning to ensure access to and uptake of vaccines for eligible populations. Through advanced planning efforts, 4 weeks after the Pfizer-BioNTech pediatric COVID-19 vaccine received emergency use authorization for U.S. children aged 5–11 years, 92% of children aged 5–11 years lived within 5 miles of a pediatric vaccine provider. Over half of these providers were in communities with high levels of social vulnerability, and 44% of these providers were pharmacies. First-dose coverage was low over the first 11 weeks (28%) but improved over time, particularly in the most socially vulnerable communities. To assess early COVID-19 vaccine access and uptake among children ages 5–11 years, study authors examined COVID-19 provider access and early vaccination coverage among children aged 5–11 years living in communities with high and low levels of social vulnerability (i.e., social and structural factors that influence health, such as poverty and crowded housing) during November 1, 2021–January 18, 2022. To maximize pediatric vaccination opportunities, federal, state, local, and pharmacy partners activated COVID-19 vaccine providers — trained to serve pediatric populations and best manage the vaccine given product and supply considerations — with particular emphasis on ensuring access in the most underserved communities. The expansion of legal authorities for the COVID-19 emergency response allowed pharmacists to vaccinate children down to 3 years of age. This was critical in increasing available providers and vaccine access through community pharmacies for children aged 5–11 years. By November 2021, 92% of all children in this age group lived within five miles of a pediatric vaccine provider. An estimated 28% of all children aged 5–11 years received their first dose of COVID-19 vaccine by 11 weeks after the Pfizer-BioNTech pediatric COVID-19 vaccine received emergency use authorization, similar to the coverage trends reached after launch of the COVID-19 vaccination program for people ages 12–15 years. While over half (53%) of vaccine providers were located in the most socially vulnerable (high scores on the social vulnerability index or SVI) communities, at 4 weeks after the program launch first-dose vaccination coverage was 32% lower in children in high than in low SVI counties.  Over the subsequent 7 weeks, this gap between high and low SVI area coverage was reduced to 24%. Likely contributors to low vaccination coverage include vaccine hesitancy among parents and caregivers. This study underscores the importance of ensuring access to vaccines, while strategies to improve vaccine uptake continue, (e.g., education, outreach, engagement of trusted providers) in order to ensure there are no missed opportunities for vaccinating children ages 5–11 years.

Tobacco Product Use and Associated Factors Among Middle and High School Students — National Youth Tobacco Survey, United States, 2021

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Youth tobacco use remains a serious public health concern in 2021, with more than 9% (approximately 2.55 million) of middle and high school students reporting currently using a tobacco product. E-cigarettes were the most common tobacco product currently used among students (cited by nearly 8% or approximately 2.06 million youth). This study assessed data from the 2021 National Youth Tobacco Survey (NYTS). Due to COVID-19 protocols, the 2021 NYTS was administered online to allow participation at home, school, or some other place, and therefore, results cannot be compared with previous NYTS results. Tobacco product use was higher among certain populations, such as students who identified as lesbian, gay, or bisexual; among students who identified as transgender; and among students who reported increased symptom severity of psychological distress. While the current use of any tobacco product was highest among students who were non-Hispanic White, non-Hispanic Black students reported the highest prevalence of current combustible tobacco product use, specifically cigars. Importantly, approximately two-thirds of students who currently use tobacco products were seriously thinking about quitting. However, multiple factors continue to promote tobacco product use and initiation among youths, including flavors (such as menthol), marketing, and misperceptions of harm. Parents, educators, youth advocates, and health care providers can help protect youths from the harms of tobacco products, including e-cigarettes, and can support and encourage youth to quit.

Previously Released SARS-CoV-2 B.1.1.529 (Omicron) Variant Transmission Within Households — Four U.S. Jurisdictions, November 2021–February 2022

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Previously Released Safety Monitoring of COVID-19 Vaccine Booster Doses Among Persons Aged 12–17 Years — United States, December 9, 2021–February 20, 2022

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Previously Released Effectiveness of COVID-19 Pfizer-BioNTech BNT162b2 mRNA Vaccination in Preventing COVID-19–Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Nonimmunocompromised Children and Adolescents Aged 5–17 Years — VISION Network, 10 States, April 2021–January 2022

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Previously Released SARS-CoV-2 Incidence in K–12 School Districts with Mask-Required Versus Mask-Optional Policies — Arkansas, August–October 2021

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• Congenital Varicella Syndrome Case — Illinois, 2021
  This report describes a fatal case of congenital varicella syndrome in a child whose mother was diagnosed with varicella (chickenpox) early in the pregnancy. Chickenpox can have severe consequences, so it’s important to assess immunity in adults and vaccinate those who are not immune, especially those of child-bearing age. On April 8, 2021, a newborn was delivered at 24 weeks gestation with congenital varicella syndrome; maternal varicella had been diagnosed at 12 weeks gestation. The infant died shortly after delivery. Congenital varicella syndrome can cause serious birth defects and occurs when the virus that causes chickenpox is passed to the fetus during pregnancy, especially in the first or second trimester. Chickenpox, a highly contagious disease, used to be very common in the United States. In the early 1990s, an average of 4 million people got chickenpox; 10,500 to 13,000 people were hospitalized and 100 to 150 people died each year. As a result of the varicella vaccination program cases, hospitalizations, and deaths have declined dramatically. Cases of congenital varicella are rare. Prior to vaccine introduction, there were an estimated 44 cases in the US. Since the start of the vaccination program in 1995, this is the third known case. This report is a reminder that chickenpox can cause severe outcomes and highlights the importance of assessing immunity in adults, including those who are pregnant or planning to be, and vaccination of eligible people without protection from chickenpox.rnational Concern under the International Health Regulations, and any poliovirus identification requires immediate reporting and prompt response.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

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.