Thermostabilization of egg grown influenza viruses

The observation that the addition of deuterium oxide to tissue culture cell harvests stabilized trivalent oral poliovirus vaccine prompted us to examine the effect of deuterium oxide on stabilization of other licensed and experimental live viral vaccines. The most striking effect afforded by deuterium oxide was on stabilization of live, attenuated influenza A and B vaccine candidates grown in the allantoic cavity of embryonated eggs. Thermostabilization with deuterium oxide is much greater than seen with standard stabilization of these live influenza vaccines with sucrose-phosphate-glutamate. Subsequently, we have shown that a similar, stabilization is provided by diluting egg allantoic fluid in water or minimal essential medium. The mechanism of action has been explored but remains uncertain. The implications of being able to stabilize influenza after harvesting from eggs have practical application for utilization of live influenza vaccines and provides a possible way to increase and standardize the potency of inactivated vaccines that may partially degrade in the inimical environment of allantoic fluid during growth and before final vaccine purification and stabilization.