North Central Public Health District says two Dry Hollow Elementary School students have lab-confirmed cases of pertussis, or whooping cough.  Health District officials say both students were contagious the last week of school, and those exposed could continue to develop pertussis until approximately July 4.  Close contacts needing to take action have been notified.  Vaccination is highly effective against pertussis, with those at most severe risk of the disease including infants under six months of age, older unvaccinated toddlers and children, and pregnant women.  The Health District strongly recommends vaccination against pertussis, which are available for a fee through your healthcare provider or NCPHD.  Children may qualify for reduced cost or free vaccines at the Health District office, call 541-506-2600 for more information.