The Omicron, or Pango lineage B.1.1.529, variant of SARS-CoV-2 carries multiple spike mutations with high transmissibility and partial neutralizing antibody (nAb) escape. Vaccinated individuals show protection from severe disease, often attributed to primed cellular immunity. We investigated T and B cell immunity against B.1.1.529 in triple mRNA vaccinated healthcare workers (HCW) with different SARS-CoV-2 infection histories. B and T cell immunity against previous variants of concern was enhanced in triple vaccinated individuals, but magnitude of T and B cell responses against B.1.1.529 spike protein was reduced. Immune imprinting by infection with the earlier B.1.1.7 (Alpha) variant resulted in less durable binding antibody against B.1.1.529. Previously infection-naïve HCW who became infected during the B.1.1.529 wave showed enhanced immunity against earlier variants, but reduced nAb potency and T cell responses against B.1.1.529 itself. Previous Wuhan Hu-1 infection abrogated T cell recognition and any enhanced cross-reactive neutralizing immunity on infection with B.1.1.529.

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The distribution of Phlebotomus papatasi in Southwest Asia is thought to be highly dependent on temperature and relative humidity. A discriminant analysis model based on weather data and reported vector surveys was developed to predict the seasonal and geographic distribution of P. papatasi in this region. To simulate global warming, temperature values for 115 weather stations were increased by 1 degree C, 3 degrees C, and 5 degrees C, and the outcome variable coded as unknown in the model. Probability of occurrence values were then predicted for each location with a weather station. Stations with positive probability of occurrence values for May, June, July, and August were considered locations where two or more life cycles of P. papatasi could occur and which could support endemic transmission of leishmaniasis and sandfly fever. Among 115 weather stations, 71 (62%) would be considered endemic with current temperature conditions; 14 (12%) additional stations could become endemic with an increase of 1 degree C; 17 (15%) more with a 3 degrees C increase; and 12 (10%) more (all but one station) with a 5 degrees C increase. In addition to increased geographic distribution, seasonality of disease transmission could be extended throughout 12 months of the year in 7 (6%) locations with at least a 3 degrees C rise in temperature and in 29 (25%) locations with a 5 degrees C rise.ImagesFigure 1. AFigure 1. BFigure 2.Figure 3.Figure 4.

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The authors identified hospitalizations for pneumonia (n = 6,522) in active-duty Navy and Marine Corps personnel during 1981-1991 from computerized inpatient records. The crude mean annual rate of pneumonia hospitalization was 77.6 per 100,000 active-duty personnel; 65% of pneumonia hospitalizations had no etiologic agent identified. The most commonly reported agents to cause pneumonia hospitalization were Streptococcus pneumoniae (12.3%), Mycoplasma pneumoniae (10.8%), other streptococcal species (2.1%), and Haemophilus influenzae (1.9%). The median age at hospitalization was 22 years. The median duration of hospital stay was 4 days and the case fatality rate was 0.4%. The authors used a 2% sample of the entire population and by means of stepwise unconditional multivariate logistic regression modeling for pneumonia found that, independent of age, the most junior Navy and Marine Corps personnel were at highest risk. Whites were at higher risk than blacks, Hispanics, or Filipinos. These results indicate that among this generally healthy US young adult military population, pneumonia hospitalization is common, often brief, and frequently without specifically identified pathogens.