Though the risk of infection during the Gemini and Mercury missions was judged to be very low because of their short durations, some precautions (such as restricted access to the crew living quarters) were still taken to reduce the risk of crew members being exposed to disease. With the increased length of missions during the Apollo program, these health risks increased. Still, this type of plan was not implemented until the Apollo 14 mission. Previous attempts to implement the program were not completed due to operational problems or conflicts with the training schedules of the crew. However, with the exposure of a prime Apollo 13 crew member to rubella, the need for a more meticulously conceived and strictly enforced program was evident.
The Flight Crew Health Stabilization Program was finally implemented starting with the Apollo 14 mission. The objective of this program was to minimize or eliminate the possibility of adverse alterations in the health of the flight crews during the immediate preflight, inflight and postflight periods. The Flight Crew Health Stabilization Program covered four elements: Clinical Medicine, Immunology, Exposure Prevention, and Epidemiological Surveillance.
Minimizing or eliminating exposure to infectious diseases was the most important part of the preventive medicine program. Diseases could be transmitted by fomites (contaminated inanimate objects), contaminated consumables (such as air, food, and water) and personal contacts. Fomites probably represented the least important source of infectious diseases; however, precautions--such as use of separate headsets and microphones for each astronaut--was practiced.
Contaminated consumables presented a greater risk. To prevent transmission of an infectious disease through the air, a closely controlled living environment was provided during the pre-launch period. All areas in which the crew members worked or resided were equipped with high-efficiency bacterial filters in all the supply air ducts. This precluded exposure to microbial agents from adjacent non-medically controlled areas and individuals. Air handling systems were well balanced in a manner that provided higher atmospheric pressure in those areas inhabited by the crew members, as compared to the atmospheric pressure outside. This served to direct air leakage from windows, doors, floors and walls away from the crew.
Foods consumed by the astronauts were also a source of potentially infectious microorganisms. Because contamination of food could be accidental as well as intentional, no set pattern of food procurement was established. The procurement of food was handled by cooks in crew quarters and monitored by the medical team members. Portions of each lot of food purchased were subjected to microbiological evaluation. Food preparation areas were inspected daily for cleanliness and maintenance of satisfactory sanitary conditions.
Drinking water, another potential source of infectious disease agents, was subjected to daily microbiological evaluations. This ensured that the municipal water treatment procedures were satisfactory and that safe water was provided to the crew. Drinking water sources were limited to drinking fountains provided in the crew quarters and working spaces.
The most important measure taken in exposure prevention was the minimization of contact with other individuals during the critical preflight period. The areas the crew could visit were limited, as well as the number of persons who could come into contact with the crew. Crew members were also isolated from potential carriers, such as transient populations (launch site visitors), high incident groups (children), and uncontrolled contacts (maintenance personnel or those persons about whom no medical information was known). Children were the most common carriers of upper respiratory and gastrointestinal infections. Therefore, astronauts were isolated for 21 days prior to flight, even from their own children.
Because it was important for all astronauts to remain in good health, the government provided a clinical medicine program for Apollo crew members and their families. The health program was initiated upon selection of the flight crew and continued as long as the astronauts were on flight status. The program provided both routine and emergency physical examinations. Complete virological, bacteriological, immunological, serological, and biochemical studies were conducted at Johnson Space Center to ensure rapid diagnosis and prompt treatment of any disease occurrence.
Serological testing was conducted on the Apollo astronauts to determine immunity levels prior to immunizations. The serological tests were performed for tetanus, syphilis, typhoid, mumps, poliomyelitis, rubella, rubeola, and yellow fever. Tuberculin skin tests were also performed. Immunizations against diphtheria, tetanus, typhoid, influenza, poliomyelitis, smallpox, and yellow fever were given to the astronauts. Mumps, rubella, and rubeola immunizations were given if no serological response was obtained. The astronauts' families were immunized for diphtheria, pertussis, tetanus, mumps, poliomyelitis, rubella, rubeola, and smallpox. Other immunizations were provided should the crew members or their families travel to endemic areas. Unfortunately, immunizations were not available for the illnesses most likely to occur--viral and bacterial infections of the respiratory and gastrointestinal tracts.
The epidemiological surveillance program was designed to ensure that individuals who came into contact with the crew (primary contacts) were healthy, thus minimizing the risk of infectious disease transmission to the crew members. Three options were considered to help minimize crew exposure to infectious agents: 1) build housing facilities for the crew and their primary contacts; 2) modify existing housing for flight crews and primary contacts. or 3) provide strict isolation of the prime and backup crew members in the crew quarters and limit personal contacts to medically approved persons. Option 3 was selected; options 1 and 2 were determined to be cost prohibitive.
A medical surveillance program, initiated three months prior to launch, began with recording medical histories and other critical information of each primary contact. Each primary contact was then subjected to an extensive physical examination approximately 60 days prior to launch. Microbiological samples were obtained to determine carriers. Based on this information, certain individuals were approved for access to flight crew members during the 21-day pre-launch isolation period.
Each primary contact and all his family members were subjected to medical surveillance during the 21-day preflight period. Primary contacts were instructed to report to the medical examination facility whenever they or any of their family became ill or had been exposed to an infectious disease. Reports of illness events were also obtained from all schools attended by children of the crew members and primary contacts. Daily reports were solicited from each school of interest concerning the total number of absences, including absences of the children of any crew member and primary contact. Additional daily reports were obtained from public health authorities in the launch site area to determine trends and incidences of specific disease events within the population where primary contacts may have had exposure.
A computerized data processing system was developed to maintain complete and up-to-date records on all crew members and primary contacts, and their families. The system linked the medical analyses laboratories at Johnson Space Center with the Medical Surveillance Office at Kennedy Space Center, thus making information on these individuals readily available.
The success of the Flight Crew Health Stabilization Program was evidenced by the absence of preflight, inflight and postflight illnesses during the Apollo 14 through 17 missions. Statistics recorded for missions prior to the Apollo 14 mission indicated that 57 percent of the prime crew members experienced some illness during the 21-day pre-launch period, as well as during flight. Monitoring the health of primary contact children proved valuable because, in approximately 30 percent of the cases of illness in primary contacts, similar illnesses had occurred previously in one or more of the family members, with the most common type of illness being upper respiratory tract infections.