Viral Content and Stability of Live Measles Vaccines

Abstract

comment. It is visualized that the following items will be included:Requirements regarding the strains to be used and the level of passage permissible;Requirements concerning the exclusion of ad¬ ventitious agents from the virus fluids using a variety of animal and tissue culture test methods ; Demonstration of clinical safety in a significant number of susceptibles-10,000 is under consider¬ ation ;Demonstration of clinical effectiveness based up¬ on an immunogenic effect in which a high percent¬ age of measles-susceptible children convert after administration of the recommended dose ;In the case of live vaccine a demonstration of the stability of the strain in terms of capacity to revert to significant virulence in man;In the case of all tissue-culture-produced vaccines it will be necessary to demonstrate freedom from neurotropic contaminants by injection into monkeys and in the case of live measles vaccine a demon¬ stration that the measles virus in the initial lots is devoid of neurovirulence;In the case of live measles vaccine requirements for the accurate determination of virus titer will be necessary, since this is directly related to the dose, while in the case of inactivated vaccine it will be necessary to set forth antigenic tests and the stand¬ ards which are to be met for such tests.Requirements for the demonstration of consistent successful production of a series of 5 lots of vac¬ cine in the case of each producer.As with all new biological products, one of the most difficult items of information to obtain will be stability of the product under conditions of actual use, yet without this information a realistic dating period cannot be set.Steps have already been initiated leading to the eventual adoption of these regula¬ tions. A set of proposed requirements for live measles vaccine has been circulated to interested scientists, and at least one meet¬ ing has been held to discuss these require¬ ments. It is anticipated that similar steps will be initiated for inactivated measles vaccine and for a standardized -globulin preparation after the conclusion of this conference. In de\reloping these series of documents the data presented this week will be of great value, and when these products eventually become available for unrestricted use, it is hoped that they will conform to the principles which Dr. G. S. Wilson so lucidly and succinctly set forth at the open¬ ing of this conference.

Pipetting Hazards in the Special Virus Cancer Program

“…Adenovirus 7 (Couch, 1963) Conjunctival swab 320 4 Adenovirus 7 (Plotkin, 1967;Couch, 1963) Ingestion 10,000 15 Measles (Markham, 1962) Subcutaneous lOb! 34 Measles (Okuno, 1962) Intranasal spray 0.2b!…”

Measles Vaccination with Reduced Dosage

“…These workers suggested that small infective doses might be satisfactory when given in a relatively large volume, but that unth this had been demonstrated 1,000 TCID50 should be retained as the standard dose. Markham (1962) also noted that low doses of measles vaccine would produce good sero-conversion rates, and felt that the main reason for having a 1,000 TCID50 dose as standard was the relative instability of the fluid vaccine.…”

A Summary of Field Experience with Live Virus Measles Vaccine

“…Stability studies on the vaccines indicated that the number of TCID50 injected at vaccination could be reliably estimated. 4 Blood the seronegative children were available for study. The temperature readings were not adjusted to oral equivalents.…”