By Saibal Gupta Kolkata, July 14 : West Bengal managed to extract 13 lakh extra doses of vaccine in the last two months from its stipulated quota only by saving the extra dose given in a vial to compensate for the wastage. Kerala is the only state after West Bengal that has recorded a negative wastage by skilfully administering the vaccine and has earned accolades from the central government. Technically the process is called 'negative wastage' which means not only ensuring zero wastage but actually eking out and administering an extra dose from each vial. State health department records said that in the last two months the state has recorded minus 7 per cent wastage of Covishield doses, an impressive feat considering the low supply of vaccines. "A vial of vaccine contains enough doses to administer 10 shots. But manufacturers add an extra dose in each vial as a "wastage factor". In most cases, a tiny amount of the vaccine gets wasted each time the vaccine is drawn into the syringe. The extra dose is added in the vial to compensate for this loss. But if the vaccinator is skilful, it is possible to save this extra dose to vaccinate 11 persons from many vials," a senior official of the health department said. "The negative vaccine wastage in Bengal is now around -7 per cent, and the quantity saved will go up further as we go on saving more doses as the inoculation drive progresses," a state family welfare officer said. In other words, for every 1 lakh doses, the state is managing 7,000 extra doses. Such efficiency was also recorded by Kerala, a feat that came in for appreciation from central government officials. In Covaxin's case, Bengal initially had 1 per cent wastage, the optimal wastage limit suggested by the Centre. This has been reduced to zero. The initial wastage was due to public inhibitions about the vaccine, sources said. A vial containing 10 doses has to be utilised within four hours of opening. There were several cases of insufficient recipients turning up during this window, leading to wastage. Official data for May show Kerala and West Bengal standing in sharp contrast to states like Jharkhand and Chhattisgarh which recorded a high 33.9 per cent and 15.7 per cent wastage respectively. The wastage for other states is lower, but still on the higher side like in Madhya Pradesh (7.3 per cent), Delhi (3.9 per cent), Gujarat (3.6 per cent) and UP (3.7 per cent). Till Tuesday evening, Bengal had administered a total of around 2,45,29,000 doses approximately, about 28 lakh doses of which were done by private vaccination centres. So far, the state has received a total of about 1.93 crore Covishield doses and 32 lakh Covaxin doses for government centres since the inoculation drive began, apart from 25 lakh doses for the private sector since May. The extra vaccination comes at a time the scanty vaccine supply to Bengal has slowed the pace of vaccination in the state. More than 3 lakh doses were being administered daily around the third week of June; the figure now is 2 lakh plus. /IANS