August 15, 2024

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Measles: Virus Transmission after Vaccination Failure

Onward Virus Transmission after Measles Secondary Vaccination Failure
Results of a systematic review aimed to assess transmission risk for measles after secondary vaccination failure (SVF). Primary vaccination failure (PVF) is failure to seroconvert after vaccination while secondary vaccination failure (SVF) is something that occurs years after that initial vaccination felt to be due to waning of immunity.So primary vaccination failure (PVF) results from a person’s failure to produce any humoral response to viral antigen (nonseroconversion) and is thought to occur in 5% of measles vaccinees. Secondary vaccination failure (SVF) seems to occur six to 26 years after the last vaccine dose and is a result of waning or incomplete immunity. SVF occurs in 2%–10% of measles vaccinated persons Here the investigators searched PubMed, Embase, and Web of Science databases. Inclusion criteria were articles describing persons who were exposed to measles-infected persons who had experienced SVF. Across the included 14 studies, >3,030 persons were exposed to measles virus from SVF cases, of whom 180 were susceptible, indicating secondary attack rates of 0%–6.25%. They identified 109 cases of SVF from the studies; 10.09% (n = 11) of case-patients transmitted the virus, resulting in 23 further cases and yielding an effective reproduction number of 0.063 (95% CI 0.0–0.5). Compare this to the >10 for unvaccinated people with measles.

COVID: Early Viral Phase

Single Monoclonal Antibodies Should Not be Used for COVID-19 Therapy: A Call for Antiviral Stewardship
We read that “It is an axiom of infectious disease practice that the use of a single agent for microbial agents with the capacity to rapidly generate escape mutants can lead to emergence or resistant microbes. Such a lesson was painfully learned over decades of clinical experience when single drug therapies led to the emergence and circulation of resistant strains. For example, during a Phase II randomized clinical trial of bamlanivimab the prevalence of treatment-emergent mAb resistant SARS-CoV-2 was 7% in the treatment group versus 0% in the control group When antimicrobial drug resistance emerges due to selection for less susceptible strains, these strains can be transmitted to others in the community and healthcare settings. This is also possible for resistance that is induced by mAbs. However, it is unlikely that the demise of the first generation mAbs is solely attributable to selection of mAb-resistant variants since SARS-CoV-2 Spike protein mutations had already been documented prior to the rollout of anti-Spike mAbs in 2021. The most likely explanation for the short clinical life of the originally deployed mAbs was that they targeted single Spike protein epitopes that were also the targets of infection- and vaccine- induced antibodies. “ The authors argue that while mAb use for PreEP is justified, single mAbs should not be used for COVID-19 therapy.

COVID: The Late Phase/PASC/Long COVID

Differentiation of Prior SARS-CoV-2 Infection and Postacute Sequelae by Standard Clinical Laboratory Measurements in the RECOVER Cohort
This study looked at 10,094 participants, 8,746 had prior SARS-CoV-2 infection, 1,348 were uninfected, 1,880 had a PASC index of 12 or higher, and 3,351 had a PASC index of zero. (Supplementary material includes a table illustrating the PASC symptoms index.) After propensity score adjustment, participants with prior infection had a lower mean platelet count, higher mean hemoglobin A1c (HbA1c) level, and urinary albumin–creatinine ratio. They comment that differences were of modest clinical significance. And they point out that among participants with prior infection, no meaningful differences in mean laboratory values were found between those with a PASC index of 12 or higher and those with a PASC index of zero. Laboratory studies that were done were complete blood count with differential, complete metabolic panel, international normalized ratio, D-dimer, lipid panel, 25-hydroxyvitamin D, thyroid-stimulating hormone, free thyroxine, hemoglobin A1c (HbA1c), high-sensitivity CRP (hsCRP), cystatin C, N-terminal pro–B-type natriuretic peptide, troponin, urinalysis, and urinary albumin–creatinine ratio (uACR). These tests were selected on the basis of their routine availability and standardized use across CLIA-certified laboratories, prior literature, and clinical expertise of the RECOVER investigators. While patients seeking care might have a compelling clinical presentation, in some cases biochemical and physiological abnormalities that are consistent with Long COVID, there remain no diagnostic biomarkers and one cannot rule out Long COVID with routine blood work.
Risk Factors for Long COVID Syndrome in Postmenopausal Women with Previously Reported Diagnosis of COVID-19
Women’s Health Initiative (WHI) is a landmark study dedicated to understanding chronic disease prevention strategies in postmenopausal women. During 1993–1998, 68,132 women enrolled into three overlapping randomized, controlled Clinical Trials (WHI-CT) and 93,676 women enrolled in a prospective Observational Study (WHI-OS). All women were postmenopausal and in the age range 50–79 years at enrollment at 40 U.S. clinical centers. Using WHI demographic and health data collected at study enrollment (1993–98) through the present day, machine learning identified the top 20 risk factors for Long COVID. These variables were tested in logistic regression models. Of n = 37,280 survey respondents, 1,237 (mean age = 83 years) reported a positive COVID-19 test and 425 (30 %) reported Long COVID. Symptoms included an array of neurological, cardio-pulmonary, musculoskeletal, and general fatigue, and malaise symptoms. Risk factors for Long COVID were a weight loss of 10 pounds or more in the previous two years, sleep problems, limited physical and mobility, previous heart-valve procedures, and rheumatoid arthritis. Physical-function risk factors for Long COVID were a limited ability to bend, kneel, stoop, or grocery shop, as well as the use of a wheelchair, walker, or crutches on level surfaces.
Long-COVID Symptom Monitoring: Insights from a Two-year Telemedicine Study
Investigators conducted interviews to evaluate Long-COVID symptoms at the two-year mark and investigated whether patients had contracted a second COVID-19 infection between the one-year and two-year follow-ups, and recorded their vaccination status. Out of 165 patients, 139 (84%) reported symptoms at the one-year follow-up, while only 101 (61%) reported symptoms at the two-year follow-up. Among patients with Long-COVID symptoms at the two-year follow-up, the majority (80, 49%) had experienced Long-COVID at the one-year follow-up, received the SARS-CoV-2 vaccine, and had not experienced a second infection between the two follow-ups. Both having Long-COVID at the one-year follow-up and contracting a second infection were significant risk factors for presenting with Long-COVID at the two-year follow-up.