Missed hepatitis B birth dose vaccine is a risk factor for incomplete vaccination at 18 and 24 months.

OBJECTIVES: To determine whether missing the HepB birth dose vaccine is a risk factor for incomplete vaccination later in childhood. METHODS: This was a retrospective cohort study of infants born over one year at an academic medical center. The "not vaccinated at birth" group consisted of all infants who did not receive the HepB birth dose vaccine by seven days of life, while the "vaccinated at birth" group included infants who did receive the birth dose. The primary outcome was vaccination status at 18 months of age, determined from the state vaccination registry. RESULTS: Infants "not vaccinated at birth" had lower vaccination rates. At 18 months, 44% of the "vaccinated at birth" group received all recommended vaccines, compared with 23% of the "not vaccinated at birth" group (p < 0.001); at 24 months, rates were 65% and 45%, respectively (p < 0.001). Over 80% of the variability in vaccination completions were related to a single latent variable, which is most likely vaccine hesitancy/refusal. CONCLUSIONS: Infants who miss the HepB birth dose vaccine are at risk for under-immunization by 18 and 24 months of age. This suggests that parents likely form opinions about vaccines long before the birth of their child; therefore, efforts to influence attitudes must begin earlier.

Experimental evidence that ovary and oviducal gland extracts influence male agonistic behavior in squids.

Recent investigations of sensory and behavioral cues that initiate sexual selection processes in the squid Loligo pealeii have determined that egg capsules deposited on the substrate provide a strong visual and chemotactile stimulus to males, even in the absence of females (1, 2, 3). The visual stimulus of egg capsules attracts males to the eggs, and when the males touch the eggs, they encounter a chemical stimulus that leads to highly aggressive fighting behavior. We have recently demonstrated that egg capsule extracts implanted in artificial egg capsules elicit this aggressive behavior (4). In this communication, we present evidence that the salient chemical factor originates in the ovary and perhaps the oviducal gland of the female reproductive tract.

Contact chemosensory cues in egg bundles elicit male-male agonistic conflicts in the squid Loligo pealeii.

Male Loligo pealeii engage in frequent agonistic bouts to gain access to female mates while aggregated at communal egg beds. Male squids are attracted to eggs in the field and in the laboratory. It was recently demonstrated that visual detection followed by physical contact with egg capsules elicited male-male aggression. We tested specific physical and chemical features of the egg capsules that may cause this strong behavioral reaction. Male squids were presented with either natural or artificial egg stimuli and scored for four selected behaviors (egg touch, egg blowing, forward-lunge grab, and fin-beating), the last two of which are highly aggressive behaviors. First, squids were presented with natural eggs versus eggs sealed in agarose-coated tubes (ESACT), which eliminated both tactile and chemical stimuli. Second, males were presented with natural eggs versus eggs sealed in agarose coated tubes containing C18 Sep-Pak-purified extracts (TCPE) from squid egg capsules, which provided chemical cues from natural eggs without the physical stimulus of the egg capsules. Third, natural eggs versus heat-denatured eggs were tested to determine whether the active factor in natural eggs is heat-labile. Squids responded aggressively when contacting natural eggs and TCPE, whereas squids did not respond after touching ESACT or denatured eggs. These results suggest that aggressive behavior is elicited by a heat-labile factor that is embedded within squid egg capsules. This chemosensory cue appears to be a contact pheromone that stimulates the agonistic interactions that characterize the mating behavior of migratory squids on inshore spawning grounds.