What's new in infectious diseases

The following represent additions to UpToDate from the past six months that were considered by the editors and authors to be of particular interest. The most recent What's New entries are at the top of each subsection.

COVID-19

Prevalence of long COVID (December 2022)

The true prevalence of long COVID-19 is unknown due to varying definitions and methods of analysis. However, a meta-analysis of 54 studies estimated that 6.2 percent of individuals who had symptomatic COVID-19 infection between March 2020 and January 2022 experienced at least one long COVID symptom [1]. These data shed light on the true prevalence of long COVID-19. Whether this rate is also reflective of infection with the omicron variant requires additional study. (See "COVID-19: Evaluation and management of adults with persistent symptoms following acute illness ("Long COVID")", section on 'Prevalence'.)

Booster doses with the bivalent COVID-19 mRNA vaccines (September 2022, Modified December 2022)

Booster doses of COVID-19 vaccines are a strategy to improve effectiveness in the setting of waning immunity and immune evasion from circulating SARS-CoV-2 variants. The US Food and Drug Administration authorized two bivalent mRNA booster vaccines that target the spike proteins of both the original SARS-CoV-2 strain and the Omicron B.4/B.5 variants (figure 1 and figure 2) [2,3]. The Centers for Disease Control and Prevention (CDC) now recommends that all individuals ≥5 years old who have completed a primary COVID-19 vaccine series (including those who already received booster doses with monovalent vaccines) receive a single booster dose with one of the bivalent vaccines at least two months after the last vaccine dose; bivalent booster recommendations for children younger than five years old depend on the primary series vaccine received (table 1) [4]. Our approach is consistent with CDC recommendations. Although clinical data evaluating bivalent vaccines are limited, their use is supported by indirect evidence from trials and observational studies in which monovalent booster doses improved vaccine efficacy against infection and severe disease and by studies that indicate at least comparable immunogenicity with bivalent versus monovalent formulations. (See "COVID-19: Vaccines", section on 'Role of booster vaccinations'.)

Nirmatrelvir-ritonavir in vaccinated individuals with COVID-19 (October 2022)

A large randomized trial previously demonstrated that nirmatrelvir-ritonavir (Paxlovid) substantively reduced hospitalization and death in unvaccinated individuals with COVID-19 and risk factors for severe disease; accumulating observational data suggest that high-risk vaccinated individuals also benefit. In a study of 1130 vaccinated adults who received nirmatrelvir-ritonavir within five days of COVID-19 diagnosis and 1130 controls matched for age, gender, race, and comorbidities, nirmatrelvir-ritonavir was associated with a lower rate of emergency department visits, hospitalization, and death (odds ratio 0.5) [5]. All 10 deaths were among those who had not been treated. In another study, nirmatrelvir-ritonavir was associated with a reduction in hospitalization from 59 to 15 cases per 100,000 person-days among mostly vaccinated patients ≥65 years old [6]. Despite the limitations of observational data, these data highlight the potential clinical impact of nirmatrelvir-ritonavir among vaccinated individuals with Omicron subvariant infection and support our recommendations to treat patients at risk for severe disease, including otherwise healthy individuals ≥65 years old, regardless of vaccination status (algorithm 1). (See "COVID-19: Management of adults with acute illness in the outpatient setting", section on 'Efficacy and rationale'.)

IVIG for vaccine-induced immune thrombotic thrombocytopenia (October 2022)

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare complication of adenoviral-vectored COVID-19 vaccines that presents with thrombocytopenia and thrombosis. Emerging evidence on management continues to support a role for intravenous immune globulin (IVIG) as a component of therapy, along with anticoagulation. In a new nonrandomized study involving 99 individuals with VITT presenting with cerebral venous thrombosis, receipt of IVIG was associated with lower mortality (29 versus 70 percent) [7]. In contrast, the choice of anticoagulant (heparin versus a nonheparin agent) and receipt of a platelet transfusion were not associated with statistically different mortality rates. We continue to suggest IVIG plus a nonheparin agent, especially if there is concern for possible heparin-induced thrombocytopenia (HIT; including delayed or spontaneous HIT). (See "COVID-19: Vaccine-induced immune thrombotic thrombocytopenia (VITT)", section on 'IVIG'.)

Vitamin D trials do not show benefit for COVID-19 outcomes (October 2022)

There is growing interest in the role of vitamin D as a facilitator of the innate immune response during SARS-CoV-2 infection. However, two recent trials evaluating the effect of vitamin D supplementation on COVID-19 outcomes did not show a benefit:

●In a trial from the United Kingdom, in which 6200 adults were randomly assigned to testing of serum 25-hydroxyvitamin D followed by daily low (800 units) or high (3200 units) dose vitamin D supplementation when the concentration was <30 ng/mL (<75 nmol/L) versus no testing/supplementation, there was no difference in the incidence or severity of COVID-19 during six months of follow-up [8].

●In a trial from Norway, in which 34,601 adults were randomly assigned to 5 mL of cod liver oil (400 units vitamin D) or placebo daily for six months, there was no difference in the incidence or severity of COVID-19 during six months of follow-up [9].

In patients with COVID-19, vitamin D supplementation may be necessary to meet the recommended intake or to treat deficiency; however, doses exceeding the upper level intake with the intention of improving COVID outcomes are not advised. (See "Vitamin D and extraskeletal health", section on 'COVID-19'.)

New guidance on COVID-19 testing before elective surgery (July 2022)

During the initial COVID-19 pandemic, many guidelines recommended universal SARS-CoV-2 testing prior to surgery, with a possible delay of elective surgery for patients who test positive. Now, an updated joint statement from the American Society of Anesthesiologists and Anesthesia Patient Safety Foundation suggests that in areas of low-to-moderate community SARS-CoV-2 transmission, institutions may choose to not require preoperative testing for asymptomatic, vaccinated patients scheduled for lower-risk procedures [10]. They continue to recommend universal preoperative testing in areas of high COVID-19 transmission and for symptomatic patients. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control", section on 'Preoperative screening and testing'.)

Novavax COVID-19 vaccine in the United States (July 2022)

In July 2022, the US Food and Drug Administration issued an emergency use authorization for NVX-CoV2373 (Novavax COVID-19 vaccine) for individuals aged 12 years or older, and the Centers for Disease Control and Prevention subsequently recommended it as an option for COVID-19 vaccination [11]. It is an adjuvanted recombinant protein vaccine, similar to other long-available non-COVID-19 vaccines. In trials conducted prior to the emergence of the Delta and Omicron variants, NVX-CoV2373 efficacy in preventing symptomatic COVID-19 was 90 percent in adults; rare cases of myocarditis were reported among vaccine recipients [12,13]. NVX-CoV2373 may be an attractive option for individuals who prefer a COVID-19 vaccine created with a more established vaccine platform. (See "COVID-19: Vaccines", section on 'Available vaccines'.)

Physical fitness and COVID-19-related morbidity (July 2022)

Evidence is growing that physical fitness confers benefit in those infected with COVID-19. In a retrospective, nationwide study performed in South Africa of over 65,000 people participating in a physical activity rewards program, those with high physical activity levels (>150 minutes/week) suffered substantially lower morbidity from complications of COVID-19 infection than those with low physical activity levels (<60 minutes/week) [14]. Patients with high activity levels prior to becoming infected experienced lower rates of hospitalization, intensive care unit admission, mechanical ventilation, and death. These findings emphasize the importance of maintaining exercise programs during the pandemic. (See "COVID-19: Return to sport or strenuous activity following infection", section on 'Impact of physical fitness on clinical course'.)

Risk of long COVID in Delta versus Omicron variants (June 2022)

Persistent symptoms following acute COVID-19 infection (eg, long COVID) are common. Recent evidence suggests that the prevalence of persistent symptoms may vary depending on the COVID-19 variant. In an observational study including over 97,000 vaccinated individuals in the United Kingdom, subsequent infection with the Omicron variant was associated with a lower risk of developing persistent symptoms compared with Delta (4.5 versus 10.8 percent) [15]. Findings were consistent regardless of the interval between vaccination and infection. However, methodologic issues (eg, self-reporting through an electronic "app" and shorter duration of follow-up for Omicron versus Delta patients) limit the interpretation of these findings, and further research is needed. (See "COVID-19: Evaluation and management of adults with persistent symptoms following acute illness ("Long COVID")", section on 'Persistent symptoms'.)

BACTERIAL INFECTIONS

Increasing invasive group A streptococcal infections among children in Europe (December 2022)

Several European countries, including England, France, Ireland, the Netherlands, and Sweden, have reported an increased rate of invasive group A streptococcal (GAS) infections among children <10 years old during the fall and winter of 2022 compared with prior years [16,17]. This increase parallels a >3-fold rise in reported cases of scarlet fever and may reflect an early GAS season coinciding with an increase in circulating respiratory viruses. No increase in antibiotic resistance has been observed among isolated GAS strains. Enhanced surveillance activities have been implemented in the affected areas and public health organizations are emphasizing the importance of early recognition of GAS infections, particularly scarlet fever, and prompt treatment. (See "Invasive group A streptococcal infections in children", section on 'Incidence'.)

Drainage or splenectomy for splenic abscess (November 2022)

Splenic abscess is an uncommon infection that typically results from a hematogenous source such as endocarditis. Along with broad-spectrum antibiotics, a procedure is often needed to remove the fluid collection. A new systematic review of splenic abscess treatment in nearly 600 patients found that approximately half were treated with percutaneous drainage and half with splenectomy [18]. There were no statistically significant differences in mortality or complications. Drainage is less invasive and was associated with trends toward lower mortality and complication rates, but this may have reflected differences in patient populations or local expertise. The choice of procedure is individualized; percutaneous drainage may be preferable to some individuals if feasible. (See "Evaluation of splenomegaly and other splenic disorders in adults", section on 'Management (abscess/infarction)'.)

Antibiotic prophylaxis against endocarditis before invasive dental procedures (September 2022)

The efficacy of antibiotic prophylaxis for prevention of infective endocarditis (IE) has not been established. A case-crossover analysis and cohort study performed in nearly 8 million individuals identified an association between invasive dental procedures (particularly extractions and oral surgery) and subsequent IE in individuals at high IE risk [19]. Antibiotic prophylaxis was associated with reduced risk of IE after these procedures. These findings support administration of antibiotic prophylaxis to individuals with high IE risk undergoing invasive dental procedures. (See "Prevention of endocarditis: Antibiotic prophylaxis and other measures", section on 'Impact of procedures on risk of endocarditis'.)

Evidence of Burkholderia pseudomallei endemicity in the southern United States (August 2022)

Melioidosis, which refers to pneumonia, skin or genitourinary infections, or sepsis caused by Burkholderia pseudomallei, occurs predominantly in regions of Asia and northern Australia, where the organism is hyperendemic. However, sporadic reports of cases unrelated to travel and environmental detection of B. pseudomallei suggest that it may be endemic in other areas, including the southern United States. In July 2022, B. pseudomallei was identified in soil and water from the Mississippi Gulf Coast region [20]. The environmental isolates were genetically linked to isolates cultured from two unrelated patients who lived in the area, had no history of travel, and presented with melioidosis in 2020 and 2022. Clinicians should be aware of the possibility of melioidosis when evaluating patients in or from this area who have consistent findings without another clear cause. (See "Melioidosis: Epidemiology, clinical manifestations, and diagnosis", section on 'Cases elsewhere globally'.)

Role of surgery for large left-sided cardiac valve vegetation (July 2022)

Patients with left-sided native valve infective endocarditis with a large (>10 mm) vegetation are at high risk for mortality, but a benefit from early valve surgery in this setting has not been established. An observational study of over 700 patients with left-sided infective endocarditis found that although patients with large vegetations had a high early mortality rate, vegetation size was not an independent predictor of mortality [21]. Among patients with large vegetations without heart failure or uncontrolled infection, the mortality rate was similar with or without valve surgery. For patients with large vegetations, we perform an individualized risk-benefit assessment comparing early surgery with expectant management based upon multiple factors including response to antibiotic therapy, presence of embolic events, and surgical risk. (See "Surgery for left-sided native valve infective endocarditis", section on 'Vegetation characteristics and risk of embolization'.)

HIV INFECTION

Elimination of perinatal HIV transmission with ART (September 2022)

Antiretroviral therapy (ART) has played a significant role in reducing the number of perinatal HIV transmissions over the past few decades. In a new analysis of 14,630 females with HIV, among the 5482 who conceived on ART and had a suppressed viral load at time of delivery, there were no perinatal HIV transmissions [22]. This study further supports the efficacy ART initiation prior to conception, when possible, and maintenance of viral suppression during pregnancy for the prevention of perinatal HIV transmission. (See "Antiretroviral selection and management in pregnant women with HIV in resource-rich settings", section on 'HIV viremia and risk of infant infection'.)

Dolutegravir not associated with adverse birth outcomes (September 2022)

Dolutegravir is a preferred antiretroviral drug for the treatment of HIV. Initial results from a surveillance study of birth outcomes in Botswana suggested a possible increased risk of neural tube defects among infants born to mothers who conceived while taking dolutegravir-based antiretroviral therapy (ART); however, subsequent data has been reassuring. In a follow-up analysis of the Botswana study, with nearly 30,000 births with ART exposure at the time of conception recorded, there was no difference in the incidence of neural tube defects with dolutegravir (used in 6000 pregnancies) versus other antiretrovirals [23]. In another observational study of over 1000 females on ART during pregnancy, dolutegravir use was not associated with adverse birth outcomes (preterm birth, low birth weight, small gestational age) [22]. Given these results, we continue to recommend dolutegravir in females of childbearing age and those who are pregnant. (See "Safety and dosing of antiretroviral medications in pregnancy", section on 'Fetal safety'.)

Shortened duration of amphotericin for treatment of cryptococcal meningitis in patients with HIV (July 2022)

In patients with HIV, treatment of cryptococcal meningitis has traditionally included two weeks of liposomal amphotericin B plus flucytosine. In resource-limited settings, wherein prolonged monitoring may be unfeasible, regimens with a shortened course of amphotericin B have been used to reduce the risk of toxicity. The World Health Organization's preferred regimen is now a single 10 mg/kg dose of liposomal amphotericin B with 14 days of flucytosine and high-dose fluconazole [24]. In a randomized trial, this regimen had comparable efficacy and less toxicity than the previously preferred regimen, which used a seven-day course of amphotericin B deoxycholate [25]. When resources allow, we still prefer two weeks of liposomal amphotericin B plus flucytosine since this regimen is established in clinical practice; patients should be monitored closely (ideally in the hospital setting), regardless of which regimen is used. (See "Cryptococcus neoformans meningoencephalitis in persons with HIV: Treatment and prevention", section on 'Preferred regimens'.)

IMMUNIZATIONS

Expanded ACIP recommendations for oral cholera vaccine (October 2022)

CVD 103-HgR (Vaxchora) is a single-dose, live attenuated oral cholera vaccine derived from Vibrio cholerae serotype O1; it was licensed by the US Food and Drug Administration and recommended by the Advisory Committee on Immunization Practices (ACIP) in 2016 for adults age 18 to 64 years traveling to areas of active cholera transmission. In 2022, the ACIP expanded the age group to include individuals age 2 to 17 years who meet these criteria [26]. Thus far, assessment of CVD 103-HgR vaccine benefit in children has been based on safety and immunogenicity data rather than direct assessment of vaccine efficacy. We are in agreement with this guidance. (See "Cholera: Clinical features, diagnosis, treatment, and prevention", section on 'For travelers to high-risk areas'.)

Updated guidelines for rabies pre-exposure prophylaxis (October 2022)

The United States Centers for Disease Control and Prevention (CDC) issued updated guidelines for pre-exposure prophylaxis for rabies [27]. Major changes include reducing the pre-exposure primary vaccination series from three doses to two doses administered seven days apart and creating five categories of risk based on an individual's risk of being exposed and likelihood of noticing the exposure (table 2). After completion of the primary vaccination series, the CDC recommends that individuals in the highest risk categories receive additional titers or boosters. If a vaccinated individual is exposed to rabies, postexposure prophylaxis varies based on their pre-exposure vaccination history or titers (table 3). We agree with these recommendations. (See "Rabies immune globulin and vaccine", section on 'Indications'.)

INFECTION CONTROL

Routine glove and instrument change prior to closure of abdominal incisions (December 2022)

Whether changing gloves and using new instruments prior to wound closure affects surgical site infection (SSI) rates is uncertain. In an unblinded cluster randomized trial of over 13,000 patients undergoing intra-abdominal surgery in low- to middle-income (LMIC) countries, the risk of SSI was lower when routine glove and sterile instrument change was performed prior to closure compared with no glove or instrument change (16 versus 19 percent) [28]. The results from this study support a theoretical advantage of changing gloves before closure as a method to reduce the risk of SSI. The LMIC setting may limit generalizability to other settings. (See "Overview of control measures for prevention of surgical site infection in adults", section on 'Surgical attire and barrier devices'.)

Topical antiseptics to reduce infection of contaminated or dirty wounds (December 2022)

The efficacy of various antiseptic agents applied preoperatively to contaminated or dirty wounds to reduce infection is not well studied. In a multiple-period, cluster-randomized, crossover trial comparing aqueous chlorhexidine gluconate with aqueous povidone-iodine for wound preparation in over 1600 open-fracture repairs, the surgical site infection (SSI) rate was 7 percent in both groups [29]. Other aspects of SSI prevention were at the provider's discretion; thus, 63 percent of patients also received an alcohol-based prewash ostensibly of the intact skin of the operative extremity and all patients received intravenous antibiotics (mean duration three days). Further study is needed to determine the optimal preparation of contaminated or dirty wounds and whether any topical agent influences SSI independent of other factors (eg, prophylactic systemic antibiotics, surgery duration, presence of ischemia). (See "Overview of control measures for prevention of surgical site infection in adults", section on 'Topical antiseptics'.)

MYCOBACTERIAL INFECTIONS

Abbreviated regimens for treatment of drug-resistant tuberculosis (December 2022)

For most patients with uncomplicated pulmonary multidrug resistant tuberculosis (MDR-TB), treatment with an abbreviated regimen (6 to 12 months) is preferred. Several new trials highlight the efficacy of specific regimens:

●In a multinational randomized trial including more than 500 patients age ≥15 years with rifampin-resistant pulmonary TB, favorable outcomes at 76 weeks were more likely with a 9-month bedaquiline- and fluoroquinolone-based oral regimen compared with a 9-month injectable-containing regimen (83 versus 71 percent), with less frequent ototoxicity (2 versus 9 percent) but comparable frequency of grade 3–4 adverse events (53 versus 50 percent) [30]. In addition, a 6-month regimen including bedaquiline and 8 weeks of an injectable agent was superior to the 9-month injectable-containing regimen (good outcome in 91 versus 69 percent). These data support preference for abbreviated bedaquiline-containing regimens. (See "Treatment of drug-resistant pulmonary tuberculosis in adults", section on 'Other bedaquiline-based regimens'.)

●In a randomized trial including 168 adults in South Korea with MDR-TB (resistant to isoniazid and rifampicin but not fluoroquinolones), treatment success rates were similar with a 9-month all-oral regimen of delamanid, linezolid, levofloxacin, and pyrazinamide compared with a >20-month injectable based-regimen (74 versus 71 percent) [31]. Serious adverse events occurred more frequently among patients treated with delamanid or linezolid (25 versus 17 percent). Pending further study, this regimen may be used as an alternative to treatment with a bedaquiline-containing regimen. (See "Treatment of drug-resistant pulmonary tuberculosis in adults", section on 'Delamanid, linezolid, levofloxacin, and pyrazinamide'.)

Linezolid dosing for drug-resistant tuberculosis (September 2022)

The bedaquiline-pretomanid-linezolid (BPaL) regimen is effective against drug-resistant tuberculosis (TB); however, the optimal linezolid dose is uncertain. In a randomized trial including 181 patients with highly resistant TB, use of this regimen with various linezolid doses (1200 mg for six months, 1200 mg for two months, 600 mg for six months, or 600 mg for two months) resulted in high success rates (93, 89, 91, and 84 percent, respectively) [32]. Peripheral neuropathy and myelosuppression occurred more frequently with the higher doses, which were more likely to be modified. Based on these findings, we administer the linezolid component of BPaL at a dose of 600 mg for 26 weeks; this group had the most favorable risk-benefit ratio with respect to adverse events and dose modifications. (See "Treatment of drug-resistant pulmonary tuberculosis in adults", section on 'Bedaquiline, pretomanid, and linezolid'.)

PARASITIC INFECTIONS

First trimester treatment of malaria with artemisinin derivatives (December 2022)

Artemisinin combination therapy (ACT) has become the preferred treatment for uncomplicated malaria in most patients, but use for treatment of chloroquine-resistant malaria in the first trimester has been avoided because of limited safety data. However, in a 2022 meta-analysis of prospective data from >700 pregnancies with confirmed first trimester exposure to ACT and >1000 pregnancies with confirmed first trimester exposure to non-ACTs, adverse pregnancy outcomes occurred less often among those who received ACT, although the result was not statistically significant (5.7 versus 8.9 percent; adjusted hazard ratio [aHR] 0.71, 95% CI 0.49-1.03) [33]. Artemether-lumefantrine accounted for 70 percent of the ACT exposures and was associated with a lower risk of adverse pregnancy outcome compared with oral quinine (4.8 versus 9.2 percent; aHR 0.58, 95% CI 0.36-0.92). Based on these data, we now suggest artemether-lumefantrine for treatment of chloroquine-resistant malaria during the first trimester. (See "Malaria in pregnancy: Prevention and treatment", section on 'Drug safety'.)

Monoclonal antibodies for malaria prevention (August 2022)

Monoclonal antibodies are a novel approach to malaria prevention; L9LS and CIS43LS both target Plasmodium falciparum sporozoites:

●In an open-label trial of healthy nonpregnant adults in the United States who underwent controlled exposure to mosquitoes carrying P. falciparum, parasitemia was prevented in 15 of 17 individuals (88 percent) who received intravenous or subcutaneous L9LS compared with none of 6 individuals who received no prophylaxis [34]. No serious adverse events were reported.

●In a randomized trial of >200 healthy nonpregnant adults in Mali who underwent smear microscopy every 2 weeks for 24 weeks, preventive efficacy of intravenous CIS43LS (40 mg/kg) against P. falciparum infection was 88 percent compared with placebo [35]. Moderate headache occurred 3.3 times more frequently with CIS43LS.

Monoclonal antibodies for malaria are currently investigational but may be a useful tool for preventing malaria in regions with antimalarial resistance and among individuals who are unable to mount an immune response to vaccination. Further study among children and pregnant patients is warranted. (See "Malaria: Epidemiology, prevention, and control", section on 'Monoclonal antibodies'.)

SEXUALLY TRANSMITTED DISEASES

False-positive syphilis screening in pregnancy (September 2022)

Screening for syphilis is a routine prenatal test; however, false positives can be more common than true positives. In a study including over 75,000 pregnancies, 183 of the 221 positive initial screening tests were false positives, and the rate did not differ between traditional algorithms and reverse algorithms [36]. These findings support the importance of confirmatory testing when initial screening for syphilis in pregnant patients yields a positive test (algorithm 2). (See "Syphilis in pregnancy", section on 'False-positive serologic tests in pregnancy'.)

VIRAL INFECTIONS, NON-HIV

Change in monkeypox terminology (December 2022)

In November 2022, the World Health Organization changed the name of the disease referred to as “monkeypox” to “mpox” [37]. This change was made to follow current best practices of not naming diseases after animals or geographic locations, and to reduce any stigma that could be associated with the original name. The virus that causes mpox will continue to be referred to as monkeypox virus until the International Committee on the Taxonomy of Viruses officially decides what the name of the virus is. (See "Epidemiology, clinical manifestations, and diagnosis of mpox (monkeypox)", section on 'Terminology'.)

Palivizumab for prevention of hospitalization during the 2022-2023 RSV season (November 2022)

During the COVID-19 pandemic, interseasonal respiratory syncytial virus (RSV) activity increased in some regions, resulting in increased pediatric hospitalizations. In regions with interseasonal activity similar to that in a typical fall-winter season, expert groups supported administration of palivizumab to eligible children outside of the typically recommended schedule. If regional RSV activity persists at high levels through the fall and winter of the 2022-2023 RSV season, the American Academy of Pediatrics supports administration of more than five consecutive doses of palivizumab to eligible children who initiated palivizumab earlier than typically recommended [38]. Information about state-level RSV activity in the United States is available from the Centers for Disease Control and Prevention. We agree with this endorsement. (See "Respiratory syncytial virus infection: Prevention in infants and children", section on 'Increased interseasonal activity during COVID-19 pandemic'.)

Outbreak of Ebola virus disease due to Sudan species in Uganda (September 2022)

Most outbreaks of Ebola virus disease in the recent past have been due to the Zaire species. On September 20, 2022, an outbreak of Ebola disease caused by Sudan species was reported in Uganda [39]. The first recognized patient presented with high fever, vomiting, diarrhea, and other signs consistent with Ebola virus disease. There are concerns about ongoing spread of this virus since vaccination with the single-dose recombinant vesicular stomatitis virus vaccine, which elicits a rapid immune response against the Zaire species, is not expected to protect against the Sudan virus. Although a two-dose vaccine that expresses the Sudan virus surface glycoprotein (among other antigens) is available, it requires a 56-day interval between doses and would offer little protection in a rapidly spreading outbreak. (See "Epidemiology and pathogenesis of Ebola virus disease", section on 'Uganda'.)

New ACIP recommendations for seasonal influenza vaccination (September 2022)

In August 2022, the Advisory Committee on Immunization Practices (ACIP) issued new recommendations for seasonal influenza vaccination in the United States [40]. The ACIP now recommends that adults aged ≥65 years preferentially receive any one of the following higher dose or adjuvanted influenza vaccines: quadrivalent high-dose inactivated influenza vaccine (HD-IIV4), quadrivalent recombinant influenza vaccine (RIV4), or quadrivalent adjuvanted inactivated influenza vaccine (aIIV4) (table 4). In addition, the approved age indication for the cell culture–based inactivated influenza vaccine has been changed from ≥2 years to ≥6 months. We are in agreement with this guidance. (See "Seasonal influenza vaccination in adults", section on 'Choice of vaccine formulation' and "Seasonal influenza in children: Prevention with vaccines", section on 'Influenza vaccines'.)

Reducing risk of monkeypox virus transmission through fecal microbiota transplant (August 2022)

In August 2022, the US Food and Drug Administration (FDA) issued guidance to reduce the risk of transmission of monkeypox virus through fecal microbiota transplants (FMT) [41]. The recommended measures include screening donors with questions directed at identifying those at high risk for monkeypox and those with recent or active monkeypox virus infection, developing exclusion criteria to exclude donors with a positive questionnaire screen, and providing informed consent to all FMT recipients regarding the possible risk of monkeypox virus transmission via FMT. Donor screening should be performed retrospectively on FMT prepared from donor stool collected on or after March 15, 2022. The FDA issued the guidance in response to the detection of monkeypox virus DNA in rectal swabs and/or stool samples from infected individuals, suggesting the potential for monkeypox virus transmission via FMT. (See "Fecal microbiota transplantation for treatment of Clostridioides difficile infection", section on 'Stool donor selection'.)

Vaccine-derived poliovirus infection in Rockland County, New York (August 2022)

In June 2022, poliovirus was confirmed in an unvaccinated, immunocompetent adult resident of Rockland County, New York hospitalized with acute flaccid lower limb weakness [42]. Vaccine-derived poliovirus type 2 was detected in the patient's stool and was also identified from wastewater samples in two neighboring New York counties, reflecting community transmission. The patient had not traveled internationally during the presumed exposure period; therefore, these findings suggest transmission within the United States from a person who received a type 2-containing oral polio vaccine abroad. Unvaccinated individuals remain at risk for paralytic poliomyelitis if they are exposed to either wild or vaccine-derived poliovirus; all individuals should stay up to date on recommended poliovirus vaccination. (See "Poliomyelitis and post-polio syndrome", section on 'Epidemiology'.)

Modified vaccinia Ankara vaccine for monkeypox postexposure prophylaxis (August 2022)

During the 2022 monkeypox outbreak, a modified vaccinia Ankara (MVA) vaccine is being used for postexposure prophylaxis after known or likely exposure. In the United States, given limited vaccine supplies, emergency use authorization was granted for intradermal MVA administration in persons ≥18 years; younger individuals should continue to receive the vaccine subcutaneously [43]. Intradermal administration uses a lower dose compared with the standard subcutaneous route, thus maximizing vaccine supply, and clinical trials suggest similar immunogenicity. However, data on the efficacy of postexposure prophylaxis and intradermal administration remain limited; patients who receive the vaccine should continue to monitor for symptoms after an exposure and reduce their risk of new exposures. (See "Vaccines to prevent smallpox, mpox (monkeypox), and other orthopoxviruses", section on 'Dose-sparing regimen'.)

Cluster of Chapare hemorrhagic fever in Bolivia (June 2022)

Chapare hemorrhagic fever was first discovered in one individual in Bolivia in 2003. No additional cases were confirmed until a cluster of nine cases in Bolivia in 2019 and 2020 revealed new information about the disease [44]. The causative virus appears to spread to humans through exposure to rodents or their excrement in agricultural settings, or through person-to-person transmission, including nosocomial transmission to health care workers. In the cluster, infections began as nonspecific acute febrile illnesses and progressed to hemorrhagic shock in up to half of patients. Management involved supportive care and strict adherence to infection control measures in health care settings. Death has occurred in half of all reported cases. (See "Emerging viruses", section on 'Chapare hemorrhagic fever'.)

OTHER INFECTIOUS DISEASES

Role of wound packing after drainage of perianal and perirectal abscess (September 2022)

After incision and drainage of a perianal or perirectal abscess, it is common practice to pack the wound, under the assumption that this will facilitate further drainage by wicking and prevent premature skin closure. In the PPAC2 trial of 443 patients with a primary perianal abscess, nonpacking, compared with packing, resulted in similar rates of fistula formation (11 versus 15 percent) and abscess recurrence (6 versus 3 percent), differences that were not statistically significant [45]. However, the nonpacking group had lower average pain scores (28 versus 38 on a 100-point visual analog scale). Given these and similar findings from two earlier small trials, we now suggest not packing the wound after drainage of perianal or perirectal abscess. (See "Perianal and perirectal abscess", section on 'Role of wound packing'.)