Following media reports raising concern about the safety of vaccines for the swine flu pandemic, the World Health Organization (WHO) issued a statement yesterday reassuring the public about the regulatory procedures for the licensing and approval of pandemic vaccines, which they said are rigorous and do not threaten safety or quality.

Dated 6 August, and issued from Geneva, where the WHO has its headquarters, the world agency said that vaccines are one of the most important medical devices for minimizing illness and deaths during a pandemic, but to be effective they have to be available quickly and in very large quantities.

If all goes to plan this swine flu pandemic will be the first where vaccines are available in time to anticipate a large surge in infections.

The 1918 pandemic killed an estimated 50 million people worldwide (according to WHO figures); there was no vaccine at all in those days.

And the most severe phases of the 1957 and 1968 pandemics were over by the time the vaccines were ready.

In 2007 the WHO got together with manufacturers, health officials and regulators worldwide to look at what would be needed to ensure the world was ready if another pandemic virus should emerge, and how to shorten the time between the arrival of a new pandemic virus and the production and availabiity of effective vaccines. A key step in that process is vaccine regulation and approval.

When they looked at the whole process and zoomed in on certain parts, they could see how to shorten some of the steps without reducing vaccine effectiveness and safety.

For example, in some cases pandemic vaccines are not entirely “new” because manufacturers can build on existing technology used to make seasonal flu vaccine, and much of the infrastructure for testing and regulatory control, including a vast reservoir of safety data, is already in place.

In this respect, approving a pandemic vaccine is similar to the steps taken to approve a new strain of seasonal flu vaccine, a routine occurrence every year when vaccines change to match the viruses circulating in the Northern and Southern Hemispheres, said the WHO.

Another example of where the timescale can be shortened without compromising vaccine quality and effectiveness is to require less data from those manufacturers who already have a vaccine licence and have said they will use the same process to make pandemic vaccine. Those procedures already exist.

The European Medicines Agency, the regulatory body for the European Union, uses a rolling review procedure. This allows manufacturers to submit data required for a single approval application as it becomes available, as opposed to waiting until the end of all the trials cited in the application.

The WHO said given the safety record of season vaccines, they expect adverse events to be rare, and like seasonal vaccines, many that occur will probably be coincidental with time of vaccination and not necessarily caused by vaccination.

However, they did say, that in order to meet the timescale, full clinical testing of the vaccines will not have completed by the time the first batches are being administered and the test results will most likely roll out in parallel with vaccination programmes.

For these reasons, the WHO advises:

“All countries administering pandemic vaccines to conduct intensive monitoring for safety and efficacy.”

They said that many countries already have plans in place to do this, and on a more positive note remind the public that mass vaccination programs can generate a lot of safety data in a short space of time, a matter of weeks, they said.

Another important factor in helping things move fast will be how data is collected and shared. The WHO said that the post-marketing surveillance data will be collected in line with protocols that follow a standard developed by the WHO so that it can be reported as it happens, in real time, and relayed worldwide via the WHO website.

According to the Los Angeles Times, the WHO also announced yesterday that manufacturers will be delivering the first doses of vaccine for pandemic H1N1 flu in September.

The first batches will be limited, but more are expected in October, said the LA Times report.

One of the media reports that questioned the safety of the new swine flu vaccine was a BBC Radio 4 documentary that alleged little or no data exists on the safety of flu vaccines in young children and pregnant women, two of the groups that will be targeted in the swine flu vaccination campaign.

There have been no trials of swine flu vaccies on pregnant women, said the BBC, which also noted that in 1976 the US government vaccinated 45 million for a swine flu outbreak that never happened.

However, following that campaign, 500 people were in a coma with a rare neurological condition called Guillame Barre syndrome and 25 of them died.

Peter Smith, Professor of tropical epidemiology at the London School of Hygiene and Tropical Medicine, who also happens to chair the WHO’s global advisory committee on vaccine safety, is one of the experts that remain mystified by the reaction.

Smith told the BBC that reaction has “not really been observed with subsequent influenza vaccines”.

He said the experience influences the way in which the US treats all new vaccines.

Health experts think it is highly unlikely that such a reaction will happen again.

— Safety of pandemic medicines (WHO).

Sources: WHO, LA Times, BBC.

Written by: Catharine Paddock, PhD