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Introduction Many vaccines require a storage temperature between 2-8 °C throughout thesupply cold chain. Multiple studies conducted at healthcare facilities worldwide document an endemicfailure to properly store vaccines, risking the efficacy of local vaccination programs.This "weak link" at the end of the cold chainis largely due to both the widespread use of inadequate domestic refrigerators for vaccine storage, and electrical power interruptions. The required specialized refrigeration equipment and backup power systemareboth prohibitively expensive for smaller facilities. Prompted by this finding, the authors sought an affordable solution for small-scale vaccine storage applications. Methods The solution presented is an aftermarketappliance designed toaccompany a wide range of domestic refrigerators.After undergoing an initial calibration step, the device effectively overridesthe refrigerator's native thermostat(s) and assumes thermoregulatory control. All interfaces between the device and the refrigerator are strictly external, allowing for installation by a layperson. Wireless temperature sensor measurements are frequently logged to a removable USB thumb drive to provide vaccine temperature traceability. The device is further equipped to charge an external battery while grid power is available, and upon grid failure automatically source refrigeration power froman attached external inverter. Results The regulator device successfullymaintained a 2-8 °C environment for all properly stored vaccine vials. Furthermore, it successfully adapted to and compensated for the individual operational characteristics of various refrigerators, and flagged those unsuitable for vaccine storage. Back-up power outage resiliency is recorded at16-25 hours for 18-28ft³sized household refrigerators using a 160Ah battery.The cost of manufacturing the device is estimated at $250 per unit. Discussion The Baylor/Rice regulator device provides an affordable refrigeration control and temperature monitoring system suitable for converting household refrigerators into effective vaccine refrigerators. The device will also be useful in areas subject to electrical grid failure. [ABSTRACT FROM AUTHOR]

We conducted the first US study using graphic-output temperature data loggers in quantifying cold chain failure. Fifty-four vaccine refrigerators of a county outpatient health system were studied. Forty-eight percent maintained temperatures of 2°C to 8°C and 24% had protracted periods of temperatures less than 0°C. The correlation between the percentage of refrigerators with freezing temperatures and the pertussis rate for each health region was r = 0.76. The findings suggest that improper vaccine storage may have contributed to recent increases in pertussis rates.

All patients with a positive reaction to the tuberculin skin test should be evaluated for weight loss, night sweats, fever, chronic cough and other signs of active tuberculosis. Chest radiographs should also be obtained in these patients. All converters receiving isoniazid should be examined monthly for signs of hepatitis and neurotoxicity. Liver function tests should be obtained at initiation of isoniazid therapy and again during the first two to four months in patients age 35 or older or with a history of alcoholism, liver disease or intravenous drug use. All cases of active tuberculosis should be reported to the local public health department. Most patients with active tuberculosis should receive isoniazid, rifampin, ethambutol and pyrazinamide daily for two weeks, followed by directly observed administration twice weekly for six additional weeks. If sputum cultures show no resistance after two months of therapy, pyrazinamide and ethambutol may be discontinued, with isoniazid and rifampin taken for an additional 16 weeks. Patients with human immunodeficiency virus infection or acquired immunodeficiency syndrome should receive the initial treatment for at least nine to 12 months, and isoniazid and rifampin for at least six months after culture conversion has occurred.