Adaptation of rubella virus to human diploid cell strains was achieved in 1964, with attenuation in the same cells being accomplished by 1967. The production of rubella vaccine in HDCS is featured by the long period required to build up high titer. High multiplicity of infection gives optimal results. Since rubella virus does not produce a cytopathic effect in HDCS, virus harvests must be made blindly and titrated individually before pooling. A unique feature of this cell-virus relationship is the continuous virus production which takes place for months. For vaccine purposes, however, virus-containing supernatant fluids may be harvested each 48 hrs from the 5th to the 21st day post-infection. Lyophilization presents no particular problems and final titers in ampoules can be as high as 10(5.0) PFU, which represents about 100 subcutaneous doses. Control of rubella vaccine presents only the problem that viral CPE is absent or mild. Therefore the presence or absence of virus may have to be determined by interference. Titration of rubella virus produced in HDCS must be by plaquing in RK13 rabbit kidney cells or by interference in cynomolgus monkey kidney cells. Rubella vaccine (RA27/3 strain) produced in HDCS has been more immunogenic than other strains and retains an ability to infect intranasally as well as subcutaneously.

Antibodies, Viral↗

PubMedDate not supplied

Methods for poliomyelitis eradication: is there a consensus?

I have been a strong advocate, for many years, for the merits of IPV for the control of poliomyelitis, and the ultimate eradication of the disease and of poliovirus from the environment (Beale AJ. Poliovaccines: time for a change in immunization policy? Lancet 1990; 335:839-842). I have also recognized how fortunate we are in the Public Health field to have such an excellent vaccine as Sabin's OPV. Dr. Foege has argued aloquently and cogently for an approach that uses both vaccines: OPV and IPV. The EPI programme has used 3 or 4 doses of OPV, but in a number of developing countries this has proved inadequate to provide satisfactory control. In South America the use of 10 or more doses has been required to bring the disease under control. A combined approach of using killed poliovaccine combined in DTP and three doses of OPV seems to be the preferred consensus solution. It would cause the minimum and, hopefully, no disruption of the existing programmes of the EPI. It would almost certainly bring forward the day when poliomyelitis will be controlled and the disease at least will be eradicated. It is clear that the sooner this is done the better. It is cheaper to do it now, although it requires more funds in the short term; and it is better for the children of the world--present and future. The extra cost of putting IPV into DTP is probably about one US$ per course, which is probably no more expensive than giving six more doses of OPV, when the total costs of administration are considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Diphtheria-Tetanus-Pertussis Vaccine↗