Effects of Radioactive Phosphorus In Vitro on Oxygen Consumption of Semen

Under the conditions of this study, the levels of radiation used did not significantly alter the oxygen consumption of boar and bull sperm. The average oxygen consumption of ninety replicates of non-treated boar semen representing thirteen different ejaculates from two boars was 201.5 micro liters of oxygen per billion sperm during the first hour of measurement, with a range of 84.6 to 295.8. The average oxygen consumption of seventy-nine replicates of treated boar semen representing twelve different ejaculates from the same two boars was 187.4 microliters of oxygen per billion sperm during the first hour of measurement, with a range of 70.2 to 264.6. The average oxygen consumption of seventeen replicates of boar seminal fluid representing six different ejaculates was 0.04 microliters of oxygen per milliliter of seminal fluid during the first hour of measurement. Seminal fluid from only three of the ejaculates consumed oxygen, while the seminal fluid from the other three ejaculates evolved an unknown gas or gases, other than carbon dioxide, instead of consuming oxygen. The average oxygen consumption of twelve replicates of non-treated bull semen representing five different semen samples from four bulls was 79.4 microliters of oxygen per billion sperm during the first hour of measurement, with a range of 29.4 to 172.1. The average oxygen consumption of six replicates of treated bull semen representing the same three semen samples from the same three bulls was 86.1 microliters of oxygen per billion sperm during the first hour of measurement, with a range of 28.2 to 157.9. Bull seminal fluid from only one out of five semen samples consumed oxygen, while eleven replicates representing four semen samples evolved an average of 15.4 microliters of an unknown gas or gases, other than carbon dioxide, per milliliter of seminal fluid during the first hour of measurement

Risk of COVID-19 after natural infection or vaccinationResearch in context

Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health

Risk of COVID-19 after natural infection or vaccinationResearch in context

Summary: Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health