Decisive Conditions for Strategic Vaccination against SARS-CoV-2

While vaccines that protect against SARS-CoV-2 are being approved, the number of available doses is limited as it may take months until the production of vaccines can meet the actual demand. The majority of available SARS-CoV-2 vaccines elicits strong immune responses when administered as prime-boost regimens. Since the immunological response to the first (“prime”) injection may provide already a substantial reduction in infectiousness and protection against severe disease, it may be more effective—under certain conditions—to vaccinate as many people as possible with only one shot, instead of administering a person a second (“boost”) shot. Such a strategic vaccination campaign may help to more effectively slow down the spread of SARS-CoV-2, reduce hospitalizations, and reduce fatalities. Yet, the conditions which make single-dose vaccination favorable over prime-boost administrations are not well understood. Here, we formulate a model that helps explore these decisive conditions as a function of the various time scales and epidemiological mechanisms at work. We study how these conditions arise from disease prevalence, vaccination rates, basic reproduction number, prime and prime-boost efficacies, prime-boost intervals, and waning rates. By combining epidemiological modeling, random sampling techniques, and decision tree learning, we find that prime-first vaccination is robustly favored over prime-boost vaccination campaigns, even for high vaccination rates, high disease prevalence, and a relatively low single-dose efficacy.

The effect of active immunization against gonadotropin-hormone-releasing-hormone on growth performance and sample joint composition of bulls

Forty-six Simmental × British Friesian bull calves were allocated to six treatment groups. In four groups (each of eight animals) half the animals were given a prime injection of gonadotropin-hormone-releasing-hormone (GnRH) either as the decapeptide or as an octapeptide (residues 3 to 10) conjugated to egg albumen. Prime injection times were at 3, 4, 5 or 6 months of age. All animals were boosted with a GnRH conjugate, similar to that used for the prime injection, at 8 months. At 8 months, six other animals were surgically castrated while the remaining eight were left as untreated bull controls. Weight gain and consumption of a barley-based diet offered ad libitum were recorded for individual animals. Blood samples were taken at a minimum of fortnightly intervals and the serum analysed for antibody titre against GnRH, testosterone and insulin-like growth factor 1 (IGF-1). Animals were slaughtered at 12 months and chemical analyses performed on the dissectible material of the 10th rib for protein, lipid, ash and water content. Greater antibody titres and a longer period of low serum testosterone were achieved with the octapeptide conjugate compared with the decapeptide. Serum IGF-1 slowly decreased following both surgical- and effective immuno-castration. There were no significant differences in food intake between the groups. Both steers and the more responsive immunocastrates had higher fat (P < 0·01), lower protein (P < 0·05) and water concentrations (P < 0·01) in tissues from a rib sample joint compared with untreated bulls. As immuno-responsiveness decreased there were indications of compensatory changes in body composition. The technique may be applicable during periods of, for example, mixed grazing for bulls.

SUMMARIOS IN INTERLINGUA

Le Uso De Amphotericina B In Le Tractamento De Disseminate Histoplasmosis Infantil Es reportate le casos de quatro patientes juvenil qui se restabliva rapidemente ab histoplasmosis disseminate post le administration intravenose de amphotericina B. Tres del patientes habeva etates de minus que 1 anno, le quarte habeva un etate de 3 annos. Le dosage diurne variava inter 0,25 e 1,0 mg/kg. Le calculate quantitate del droga esseva solvite in 5% de dextrosa in aqua, de maniera que un concentration de 1 mg/10 ml non esseva excedite. Le rapiditate del infusion esseva regulate de maniera que le dosage esseva administrate in le curso de un periodo de 6 horas. Iste therapia intravenose esseva continuate durante 4 septimanas in duo del patientes, durante 25 dies in le tertie, e durante 21 dies in le ultime. Culturas de medulla ossee resultava in crescentias de Histoplasma capsulatum in le casos del tres infantes sed non in le caso del patiente de etate plus alte. In iste ultime caso, le diagnose esseva confirmate per un test positive con gel de precipitina in agar. Mal de capite, nausea, e vomito es precoce manifestationes toxic del therapia, e elevationes del nitrogeno non proteinic in le sanguine esseva notate in le absentia de altere signos de morbo renal. Un del patientes disveloppava un reaction febril durante omne infusion, e a tres occasiones albuminuria esseva notate. Un del infantes habeva algor, febre, e un reaction anaphylactoide post le prime injection. Isto esseva apparentemente supprimite per drogas antihistaminic e epinephrina, le quales esseva discontinuate post le dece-secunde die del tractamento sin que le reactiones retornava. Le altere duo patientes habeva nulle serie reactiones de toxicitate.