# 3522
Tomorrow CSL Ltd will begin the first round of human testing of their H1N1 pandemic vaccine. This limited test will involve 240 volunteers, and should give us . . . perhaps a month from now . . . the first working data on how well the vaccine protects.
First this story, from the AP. Then a brief discussion about vaccine testing.
Human trials of swine flu drug start in Australia
SYDNEY – An Australian pharmaceutical company will begin trials Wednesday of its experimental swine flu vaccine.
CSL Ltd. will test the vaccine on 240 volunteers between the ages of 18 and 64 starting at Royal Adelaide Hospital in Australia's south, the company and media reports said.
The trial will involve participants receiving two injections of the vaccine, three weeks apart, and will compare a standard dosage with an increased dosage. Doctors will be looking to find at what dose volunteers develop an appropriate immune response.
"We appreciate that new influenza strains like the swine flu can surprise us with properties that mean they might require higher dosing and two injections rather than one to provoke the desired level of immune response in humans," Dr. Russell Basser, the company's global director of clinical development, said in a statement.
Dr. Rachel David, speaking for the company, said 400 children will also be involved in the vaccine trial.
The two things we are most interested in from these human studies are the safety of this vaccine, and the most appropriate dose. Since the antigen needed to make the vaccine will be in short supply, the lower the dose, the more people that can be vaccinated.
Right now, it is anticipated that it will take two shots . . .3 to 4 weeks apart, to generate sufficient immunity. This study should help answer that question regarding the CSL vaccine, and probably give us some clues over how other vaccine candidates will behave.
The safety question is one that will be more difficult to ascertain. Generally, serious side effects only appear in 1 out of 10,000 or perhaps 1 out of 100,000 people.
Detecting that kind of a rare reaction with a sample of just a few hundred people is unlikely. Luckily, flu vaccines usually have a low incidence of adverse side effects. The notable exception of course was 33 years ago.
During the 1976 swine flu vaccination program (see Deja Flu, All Over Again) as many as 500 recipients (out of 40 million people) developed a rare neuromuscular disease, and 25 died.
There are hopes that the world can deliver several billion doses of flu vaccine to the arms of its population over the next 12 months, a feat that has never been attempted before.
With that many people receiving jabs, it is likely that at least a few hundred serious vaccine-related side effects will be generated.
We really won’t know exactly how safe or effective this (or any) vaccine is until it has been given to millions of people, and proper surveillance and follow-up has been done.
There are no guarantees in life, and certainly no guarantees when it comes to vaccines. Like all drugs, even aspirin, there is a risk – reward tradeoff involved.
In most cases, however, the risks of getting influenza far outweigh the risks of getting the vaccine (see Flu Math).
This year, of course, there are a couple of complicating factors.
First, some countries intend to use adjuvants, or proprietary immune boosters, to lower the amount of antigen required to immunize someone.
Adjuvants have been used to boost the effectiveness of flu vaccines in the elderly in Europe, but have not been widely used in young adults or children. Some doctors and scientists have expressed concerns over their use, particularly in children, until more studies are conducted.
The United States, while purchasing adjuvants, seems reluctant to use them unless it is deemed absolutely necessary.
Second, normally it takes several months of human trials, and analyzing data, before a vaccine is certified for use. There are plans in some countries to try to `fast-track’ this process, in order that vaccinations begin as soon as possible.
While it is unlikely that serious problems will crop up with this vaccine, we really won’t know until it has been given to millions of people.
Just like every year.
