Friday, December 17, 2010

Lancet: Immunogenicity and safety Of Adjuvanted Flu Vaccines

 



# 5154

 

 

Should the next pandemic prove deadlier than the last, the ability to rapidly produce and distribute a safe and effective vaccine could prove invaluable in the saving of countless lives.

 

The time it takes from the identification of a novel virus to having the first doses of vaccine ready to go into people’s arms is measured in months. And then it may take 3 or 4 more weeks, and a second (booster) shot, before a vaccine recipient can mount a good antibody response.

 

A fast moving pandemic virus could easily spread around the world before a vaccine could be made widely available.

 

While there are new, faster vaccine manufacturing techniques on the horizon, right now the use of adjuvants to stretch limited antigen supplies – and to invoke a stronger immune response from a single shot – are viewed by many health officials as our best option to reduce this logistical nightmare.

 

Adjuvants are proprietary additives put into vaccines that increase the immune response, and thereby reduce the amount of precious antigen required for each shot.

 

They were widely used during the 2009 pandemic in Europe and Canada, although they were not utilized in American and Australian vaccines – partly because of public resistance to the idea.

 

Today The Lancet has a study that looked at, and compared, the safety and immunogenicity of GSK’s adjuvanted (AS03A) H1N1 pandemic vaccine and Baxter’s non-adjuvanted 2-Dose pandemic vaccine.

 

The bottom line: 

 

Researchers found that the adjuvanted split-virus vaccine achieved a stronger and faster immune response than the whole-virus non-adjuvanted vaccine.

 

They also found that a single antigen-dose sparing adjuvanted vaccination mounted a sufficient immune response in adults and adolescents, although the elderly might require a second shot.

 

Safety of the two vaccines was comparable, although recipients of the adjuvanted vaccine were more likely to report injection site soreness, and general complaints (malaise, fever, headaches) than did those who received the non-adjuvanted vaccine.

 

 

It is worth noting that the use of laboratory antibody titers to gauge a vaccine’s effectiveness in preventing infection isn’t an exact science.  It just happens to be the best yardstick we have, short of exposing vaccinated individuals to a virus and seeing how many get sick.

 

 

Although registration is required, you can read the abstract at the link below:

 

The Lancet Infectious Diseases - 17 December 2010
DOI: 10.1016/S1473-3099(10)70296-6

Immunogenicity and safety of a two-dose schedule of whole-virion and AS03A-adjuvanted 2009 influenza A (H1N1) vaccines: a randomised, multicentre, age-stratified, head-to-head trial


Prof Karl G Nicholson FRCP,Prof Keith R Abrams PhD,Sally Batham BA,Tristan W Clark MRCP,Katja Hoschler PhD,Wei Shen Lim FRCP,Marie-Jo Medina MS,Jonathan S Nguyen-Van-Tam FFPH,Robert C Read FRCP,Fiona C Warren PhD,Maria Zambon PhD


 

While  a good deal of concern was expressed last year over the use of adjuvanted vaccines in Europe – and those concerns likely influenced many people’s decision not to take the pandemic jab – thus far, there has been no evidence to indicate that these adjuvants posed any sort of increased health risk.

 

As we get more reassuring studies, and more experience with these adjuvants, the public’s comfort level with them will hopefully improve.   

 

For now, the idea of incorporating adjuvants into flu vaccines  . . . at least here in the United States . . .  remains a tough sell.