prevalence

Importance Metabolic dysfunction–associated steatotic liver disease (MASLD) includes a range of liver conditions, progressing from isolated steatosis (characterized by fat accumulation in the liver without inflammation) to metabolic dysfunction–associated steatohepatitis (MASH), which involves fat accumulation and inflammation in the liver. The presence of MASLD is associated with increased morbidity and mortality due to liver-related complications, hepatocellular carcinoma, cardiovascular disease, and certain extrahepatic cancers.

Observations The most common chronic liver disease worldwide, MASLD affects approximately 30% to 40% of the general adult population globally (with varying prevalence across continents), including approximately 60% to 70% of individuals with type 2 diabetes and approximately 70% to 80% of those with obesity. It is typically diagnosed based on an ultrasonographic finding of hepatic steatosis, along with at least 1 of 5 features of the metabolic syndrome (abdominal overweight or obesity, prediabetes or type 2 diabetes, hypertension, elevated level of plasma triglycerides, and low level of high-density lipoprotein cholesterol) for women who consume less than 140 g/wk of alcohol (<2 standard drinks/d) and for men who consume less than 210 g/wk (<3 standard drinks/d) and have no other known causes of steatosis such as use of a particular medication (eg, corticosteroids, tamoxifen, or methotrexate), hepatitis C, or iron overload. Other risk factors for MASLD include older age (≥50 years) and male sex (male:female ratio approximately 2). The Fibrosis-4 index (a scoring system incorporating age, serum levels of aspartate aminotransferase and alanine aminotransferase, and platelet count) and vibration-controlled transient elastography (a noninvasive imaging technique) are commonly used to stage hepatic fibrosis in patients with MASLD. Cardiovascular disease is the leading cause of death, followed by certain extrahepatic cancers (primarily gastrointestinal, breast, and gynecologic cancer) and liver-related complications, including cirrhosis, hepatic decompensation (ascites, hepatic encephalopathy, or variceal bleeding), and hepatocellular carcinoma. First-line treatment of MASLD involves behavioral modifications (including hypocaloric low-carbohydrate and low-fat diets, physical exercise, and avoidance of alcohol) and management of type 2 diabetes, obesity, hypertension, and hyperlipidemia. Bariatric surgery should be considered for patients with MASLD and a body mass index greater than 35. Resmetirom (a liver-directed, thyroid hormone receptor β-selective agonist) and subcutaneous semaglutide (a glucagon-like peptide-1 receptor agonist) are conditionally approved by the US Food and Drug Administration (FDA) for the treatment of adults with MASH who have moderate to advanced fibrosis.

Conclusions A highly prevalent condition among adults worldwide, MASLD is associated with liver-related complications, hepatocellular carcinoma, cardiovascular disease, and certain extrahepatic cancers. First-line treatment includes behavioral modifications, including a weight-reducing diet, physical exercise, and avoidance of alcohol. Resmetirom and semaglutide are conditionally FDA-approved medications for the treatment of adults with MASH and moderate to advanced fibrosis.

Low back pain typically defined as pain below the costal margin and above the inferior gluteal folds with or without leg pain 1 is worldwide the most prevalent and most disabling of the conditions that are considered to benefit from rehabilitation 2 In a systematic review that included 165 studies from 54 countries the mean point prevalence of low back pain in the general adult population was approximately 12 with a higher prevalence among persons 40 years of age or older and among women the lifetime prevalence was approximately 40 3 Low back pain is classified as specific pain and other symptoms that are caused by specific pathophysiological mechanisms of nonspinal or spinal origin or nonspecific back pain with or without leg pain without a clear nociceptive-specific cause 4 Nonspinal causes of specific low back pain include hip conditions diseases of the pelvic organs e g prostatitis and endometriosis and vascular e g aortic aneurysm or systemic disorders spinal causes include herniated disk spinal stenosis fracture tumor infection and axial spondyloarthritis Lumbar disorders with radicular pain due to nerve-root involvement have a higher prevalence 5 to 10 than other spinal causes the two most frequent causes of such back pain are herniated disk and spinal stenosis 5 The overall prevalence of the other spinal disorders is low among patients with acute low back pain For example among 1172 patients who presented to primary care clinicians in Australia with acute low back pain only 11 0 9 were found to have serious spinal conditions mostly fractures during 1 year of follow-up 6 The authors of a Dutch study that involved primary care patients reported axial spondyloarthritis in almost one quarter of adults 20 to 45 years of age who presented with chronic low back pain 7 although these findings have not been replicated In contrast to low back pain caused by specific identifiable causes nonspecific low back pain probably develops from the interaction of biologic psychological and social factors 4 and it accounts for approximately 80 to 90 of all cases of low back pain 1 Low back pain is usually classified according to pain duration as acute 6 weeks subacute 6 to 12 weeks or chronic 12 weeks

The emergence of food allergies in children is crucial for various medical fields seeking a viable strategy for allergy prevention. The most well-recognized approach adopted by numerous health care and government institutions hinges on the delay in the introduction of food allergens, which supposedly protects infants from sensitization and decreases the possibility of allergy development. However, recent experimental findings indicate that the benefits of this approach might be overestimated, as early exposure to allergenic foods has been shown to yield more advantageous outcomes. Multiple investigations on the causes of allergic diseases report that avoiding food allergies might be related to early consumption of these allergens. Alternatively, delaying the contact with allergenic nourishments, explored in contemporary research, has been proven to result in a higher prevalence of allergies among children, originating such conditions as atopic diseases and extreme sensitization to foods. The current paper compares the two prominent strategies of allergenic food introduction, gathering the most pertinent modern evidence to distinguish whether exposure to food allergens should be delayed or advanced.

This report updates the 2020–21 recommendations of the Advisory Committee on Immunization Practices (ACIP) regarding the use of seasonal influenza vaccines in the United States (MMWR Recomm Rep 2020;69[No. RR-8]). Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. For each recipient, a licensed and age-appropriate vaccine should be used. ACIP makes no preferential recommendation for a specific vaccine when more than one licensed, recommended, and age-appropriate vaccine is available. During the 2021–22 influenza season, the following types of vaccines are expected to be available: inactivated influenza vaccines (IIV4s), recombinant influenza vaccine (RIV4), and live attenuated influenza vaccine (LAIV4).

The 2021–22 influenza season is expected to coincide with continued circulation of SARS-CoV-2, the virus that causes COVID-19. Influenza vaccination of persons aged ≥6 months to reduce prevalence of illness caused by influenza will reduce symptoms that might be confused with those of COVID-19. Prevention of and reduction in the severity of influenza illness and reduction of outpatient visits, hospitalizations, and intensive care unit admissions through influenza vaccination also could alleviate stress on the U.S. health care system. Guidance for vaccine planning during the pandemic is available at https://www.cdc.gov/vaccines/pandemic-guidance/index.html. Recommendations for the use of COVID-19 vaccines are available at https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/covid-19.html, and additional clinical guidance is available at https://www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-v....

Updates described in this report reflect discussions during public meetings of ACIP that were held on October 28, 2020; February 25, 2021; and June 24, 2021. Primary updates to this report include the following six items. First, all seasonal influenza vaccines available in the United States for the 2021–22 season are expected to be quadrivalent. Second, the composition of 2021–22 U.S. influenza vaccines includes updates to the influenza A(H1N1)pdm09 and influenza A(H3N2) components. U.S.-licensed influenza vaccines will contain hemagglutinin derived from an influenza A/Victoria/2570/2019 (H1N1)pdm09-like virus (for egg-based vaccines) or an influenza A/Wisconsin/588/2019 (H1N1)pdm09-like virus (for cell culture–based and recombinant vaccines), an influenza A/Cambodia/e0826360/2020 (H3N2)-like virus, an influenza B/Washington/02/2019 (Victoria lineage)-like virus, and an influenza B/Phuket/3073/2013 (Yamagata lineage)-like virus. Third, the approved age indication for the cell culture–based inactivated influenza vaccine, Flucelvax Quadrivalent (ccIIV4), has been expanded from ages ≥4 years to ages ≥2 years. Fourth, discussion of administration of influenza vaccines with other vaccines includes considerations for coadministration of influenza vaccines and COVID-19 vaccines. Providers should also consult current ACIP COVID-19 vaccine recommendations and CDC guidance concerning coadministration of these vaccines with influenza vaccines. Vaccines that are given at the same time should be administered in separate anatomic sites. Fifth, guidance concerning timing of influenza vaccination now states that vaccination soon after vaccine becomes available can be considered for pregnant women in the third trimester. As previously recommended, children who need 2 doses (children aged 6 months through 8 years who have never received influenza vaccine or who have not previously received a lifetime total of ≥2 doses) should receive their first dose as soon as possible after vaccine becomes available to allow the second dose (which must be administered ≥4 weeks later) to be received by the end of October. For nonpregnant adults, vaccination in July and August should be avoided unless there is concern that later vaccination might not be possible. Sixth, contraindications and precautions to the use of ccIIV4 and RIV4 have been modified, specifically with regard to persons with a history of severe allergic reaction (e.g., anaphylaxis) to an influenza vaccine. A history of a severe allergic reaction to a previous dose of any egg-based IIV, LAIV, or RIV of any valency is a precaution to use of ccIIV4. A history of a severe allergic reaction to a previous dose of any egg-based IIV, ccIIV, or LAIV of any valency is a precaution to use of RIV4. Use of ccIIV4 and RIV4 in such instances should occur in an inpatient or outpatient medical setting under supervision of a provider who can recognize and manage a severe allergic reaction; providers can also consider consulting with an allergist to help identify the vaccine component responsible for the reaction. For ccIIV4, history of a severe allergic reaction (e.g., anaphylaxis) to any ccIIV of any valency or any component of ccIIV4 is a contraindication to future use of ccIIV4. For RIV4, history of a severe allergic reaction (e.g., anaphylaxis) to any RIV of any valency or any component of RIV4 is a contraindication to future use of RIV4.

This report focuses on recommendations for the use of vaccines for the prevention and control of seasonal influenza during the 2021–22 influenza season in the United States. A brief summary of the recommendations and a link to the most recent Background Document containing additional information are available at https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/flu.html. These recommendations apply to U.S.-licensed influenza vaccines used according to Food and Drug Administration–licensed indications. Updates and other information are available from CDC’s influenza website (https://www.cdc.gov/flu); vaccination and health care providers should check this site periodically for additional information.