Friday, March 19, 2010

Revised recommendations for Rabies postexposure prophylaxis

Previously, Advisory Committee Immunization Practices recommended a 5-dose rabies vaccination regimen with human diploid cell vaccine (HDCV) or purified chick embryo cell vaccine (PCECV). These new recommendations reduce the number of vaccine doses to four. The reduction in doses recommended for PEP was based in part on evidence from rabies virus pathogenesis data, experimental animal work, clinical studies, and epidemiologic surveillance. These studies indicated that 4 vaccine doses in combination with rabies immune globulin (RIG) elicited adequate immune responses and that a fifth dose of vaccine did not contribute to more favorable outcomes. For persons previously unvaccinated with rabies vaccine, the reduced regimen of 4 1-mL doses of HDCV or PCECV should be administered intramuscularly. The first dose of the 4-dose course should be administered as soon as possible after exposure (day 0). Additional doses then should be administered on days 3, 7, and 14 after the first vaccination. ACIP recommendations for the use of RIG remain unchanged. For persons who previously received a complete vaccination series (pre- or postexposure prophylaxis) with a cell-culture vaccine or who previously had a documented adequate rabies virus-neutralizing antibody titer following vaccination with noncell-culture vaccine, the recommendation for a 2-dose PEP vaccination series has not changed. Similarly, the number of doses recommended for persons with altered immunocompetence has not changed; for such persons, PEP should continue to comprise a 5-dose vaccination regimen with 1 dose of RIG. Recommendations for pre-exposure prophylaxis also remain unchanged, with 3 doses of vaccine administered on days 0, 7, and 21 or 28. Prompt rabies PEP combining wound care, infiltration of RIG into and around the wound, and multiple doses of rabies cell-culture vaccine continue to be highly effective in preventing human rabies. 
Source: accessed on March 19, 2010

'Source-sink' dynamics in polio transmission

  • Sources are areas or location where local reproductive success is greater than local mortality (>0)
  • Sinks are areas where individuals are reproducing, but the net reproductive rate is <0 (not replacement)
  • Sinks will eventually become extinct if they do not receive immigrants from other areas.
In polio virus transmission it is found that if from one place the virus is eradicated but it may come from other place where polio virus is still circulating, thus maintaining the transmission. For example, Uttar Pradesh and Bihar are acting as 'sources' and the other places in India from where the polio virus transmission has been reduced act as 'sinks'.

Thursday, March 18, 2010

Food enrichment vs. fortification

Many a times we come across these terms on packets of food items and get confused, as more or less they seem to mean the same. Food enrichment is in fact the addition of nutrients so as to restore the amount lost by processing, storage etc. For example, addition of vitamin C to orange juice in order to compensate for the loss due to processing etc. is enrichment. On the other hand, fortification is the addition of those nutrients to food items that was not naturally present in them. Addition of Iodine to common salt is therefore an example of food fortification.