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There has been a lot of hype surrounding the swine flu since the first casualties appeared in Mexico in early spring this year. The World Health Organisation (WHO) quickly raised the alert level warning of a coming pandemic. As a result, pharmaceutical companies were pressured to strongly increase the production of antiviral drugs as urgent treatments were required, but they were also encouraged to hastily produce preventive vaccines.

There are two approved antiviral drugs for influenza that are available for treatment of pandemic H1N1 influenza. These are the neuraminidase inhibitors oseltamivir and zanamivir, more commonly known by their trade names Tamiflu and Relenza.

While the WHO recommends treatment with either oseltamivir or zanamivir for patients “who initially present with severe illness or whose condition begins to deteriorate” or for patients “at risk for serious disease”, “in general, WHO does not recommend the use of antiviral drugs for prophylactic purposes“. ”Individuals that have been identified as “at-risk” of more complicated or severe illness associated with infection by influenza virus include:

• pregnant women (particularly in the later stages of pregnancy);
• infants and children (<5 years);
• patients with chronic health conditions, such as cardiovascular, respiratory or liver disease, or diabetes;
• patients with immunosuppression related to treatment for transplant surgery, cancer, or due to other diseases.

At this time, WHO considers the overall severity of the influenza pandemic to be moderate. This assessment is based on scientific evidence available to WHO, as well as input from its Member States on the pandemic’s impact on their health systems, and their social and economic functioning.

The moderate assessment reflects that:

• Most people recover from infection without the need for hospitalization or medical care.
• Overall, national levels of severe illness from influenza A(H1N1) appear similar to levels seen during local seasonal influenza periods, although high levels of disease have occurred in some local areas and institutions.
• Overall, hospitals and health care systems in most countries have been able to cope with the numbers of people seeking care, although some facilities and systems have been stressed in some localities.”

However, regarding the preventive role of flu vaccines, the WHO states that “influenza vaccines are one of the most effective ways to protect people from contracting illness during influenza epidemics and pandemics“ and that “WHO is working closely with manufacturers to expedite the development of a safe and effective vaccine but it will be some months before it is available.”

Furthermore, concerning the safety and approval of the pandemic influenza A(H1N1) vaccines, the WHOs position is as follows:

Will new pandemic influenza A (H1N1) vaccines be safe?

Licensed vaccines, including influenza vaccines, are held to a very high standard of safety. Likewise, all possible precautions will be taken to ensure safety of new pandemic vaccines and results from clinical trials, currently ongoing or soon to be initiated, will be taken into consideration by the regulatory authorities in their decision to license pandemic vaccines. In early June, WHO held a consultation of experts which reviewed the safety of adjuvants, or substances added to vaccines to make them more effective; no significant safety concerns were identified. Vaccine safety will be carefully monitored through post-marketing surveillance.

How can a repeat of the 1976 swine flu vaccine complications (Guillain-Barré syndrome) experienced in the United States of America be avoided?

Guillain-Barré Syndrome (GBS) is an acute disorder of the nervous system. It sometimes develops following a variety of infections, including influenza. Studies suggest that seasonal influenza vaccines could sometimes be associated with an increased risk of Guillain-Barré syndrome on the order of one to two cases per million vaccinated persons. During the 1976 influenza vaccination campaign, about 10 persons per million vaccinated persons developed GBS which stopped the vaccination campaign and led to the withdrawal of the vaccine.

The reason why GBS developed in association with that specific vaccine has never been firmly established. The potential for the development of a similar risk with future vaccines can never be firmly excluded. However, the influenza A (H1N1) vaccine will be manufactured according to established standards and post marketing surveillance will be conducted to monitor potential development of any serious adverse events following administration of vaccine. Safety monitoring systems are an integral part of strategies for the implementation of the new pandemic influenza vaccines.

Who will approve (license) new influenza A (H1N1) vaccines for use?

Regulatory approval for new influenza A (H1N1) vaccines will be conducted by national authorities. National regulatory authorities have put into place expedited processes that do not compromise on the quality and safety of the vaccine.

One may legitimately question how the experts the WHO has consulted with may reasonably conclude that there are no significant safety concerns, while at the same time admitting that a reoccurrence of the GBS may not be excluded with future vaccines. This is particularly preoccupying when considering that the Centers for Disease Control and Prevention acknowledge that the majority of influenza vaccines distributed in the United States currently contain Thimerosal, a mercury based preservative. The table below shows which influenza A (H1N1) vaccines are currently being produced and by which pharmaceutical companies.

Although some vaccines only contain trace amounts of Thimerosal and the statistics may not necessarily lead to the conclusion that Thimerosal is a toxic substance, some patients may understandably prefer to have a Thimerosal-free flu shot or not have a flu shot at all! In some cases though, the question is whether they’ll be given a right to chose.

It does raise some concerns to learn that vaccination campaigns have been initiated whilst clinical trials haven’t even been completed yet. You can find more interesting information over at cafemom!

UPDATE: The Washington Post has just published an article revealing how worried americans are about the swine flu and how skeptical they are about the vaccines safety. For those interested in the numbers, the article is supplemented with a Washington Post-ABC News poll examining public opinion regarding the swine flu and vaccinations.