While neurophysiological dysfunction contributes to whole muscle weakness, there is also a reduction in the force generating capacity of individual muscle cells independent of alpha motor neuron activation. Muscle Nerve, 2018.
Background
In response to reports of thrombosis with thrombocytopenia syndrome (TTS) post-vaccination, the Johnson & Johnson (J&J) vaccine was paused and then restarted in April 2021. Our objective was to assess whether this pause adversely impacted vaccine confidence.
Methods
Two large internet-based surveys were conducted in the US among adults to measure knowledge, attitudes and perceptions of the J&J vaccine pause and rates of vaccine hesitancy among unvaccinated persons before, during and after the pause.
Results
Among 66% of respondents aware of the pause, 44% identified blood clots as the reason for the pause without prompting. The impact of the pause on vaccine behavior among unvaccinated persons and perception of the vaccine safety system was mixed and modified by trust in the public health authorities. Those who were less willing to get vaccinated because of the pause were less inclined for all vaccines, not only the J&J product. Moreover, a notable proportion (22.1%) of the small number of persons (n = 30) vaccinated with the J&J vaccine after the pause reported not receiving information about the risk of TTS. The proportion of unvaccinated persons who were hesitant was increasing before and during the pause and then leveled off after the pause.
Conclusions
The J&J vaccine pause is unlikely to be a major barrier to vaccine uptake. Public attitudes about vaccines may be more resilient than appreciated, especially when safety issues are investigated with transparent communication. This paper has important implications for messaging and program administration with future vaccine-specific adverse events. Efforts may be warranted to ensure all persons being offered the J&J vaccine are made aware of the risk of TTS.
Chronic rotator cuff tears are a common source of shoulder pain and disability. Patients with rotator cuff tears often have substantial weakness, fibrosis, and fat accumulation which limit successful surgical repair and postoperative rehabilitation. The Murphy Roths Large (MRL) strain of mice have demonstrated superior healing and protection against pathological changes in several disease and injury conditions. We tested the hypothesis that, compared to the commonly used C57Bl/6 (B6) strain, MRL mice would have less muscle fiber atrophy and fat accumulation, and be protected against the loss in force production that occurs after cuff tear. Adult male mice B6 and MRL mice were subjected to a rotator cuff tear, and changes in muscle fiber contractility and histology were measured. RNA sequencing, and shotgun metabolomics and lipidomics were also performed. Muscles were harvested one month after tear. B6 and MRL mice had a 40% reduction in relative muscle force production after rotator cuff tear. RNA sequencing identified an increase in fibrosis-associated genes and a reduction in mitochondrial metabolism genes.Markers of glycolytic metabolism increased in B6 mice, while MRL mice appeared to increase amino acid metabolism after tear. There was an accumulation of lipid after injury, although there was a divergent response between B6 and MRL mice in the types of lipid species that accrued.There were strain-specific differences between the transcriptome, metabolome, and lipidome of B6 and MRL mice, but these differences did not protect MRL mice from weakness and pathological changes after rotator cuff tear.
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