H1N1 Vaccine Arriving

GENEVA/LONDON: The first vaccines to combat A(H1N1) flu should be approved and ready for use in some countries from September, the World Health Organization said on Thursday.

A nurse displays an H1N1 influenza kit which contains protective face masks and Tamiflu in the dedicated hospital room for arriving patients who are suspected to be ill with the flu at the CHRU Hospital in Lille, northern France, August 6 2009. [Agencies]

Marie-Paule Kieny, WHO director of the Initiative for Vaccine Research, also said vaccine production yields were improving, following a disappointing start that triggered some worries about supplies.

One of the virus strains used by vaccine makers now seems to be yielding the same amount as seasonal vaccine, while early indications were that pandemic H1N1 yields might be only 30 percent of normal.

"I don't want to say too early that the question has been resolved but it really seems that we have found a way to go round this problem," Kieny told reporters. "We are on track in development."

First results from clinical trials are expected early next month and these tests will show whether one or two doses are needed to provide immunity - another big swing factor in determining how many people can be vaccinated.

Once initial clinical trial results are in, regulators will be able to approve the vaccines from next month and the first countries are expected to start mass vaccination programmes, Kieny added.

The H1N1 flu outbreak, declared a pandemic on June 11, has spread around the world and could eventually affect 2 billion people, according to WHO estimates.

Fears the strain could become resistant to the anti-viral drug Tamiflu have underscored the need to get vaccines to market quickly. The H1N1 vaccines would be given separately from regular seasonal flu shots.

Leading flu vaccine makers include Sanofi-Aventis, GlaxoSmithKline, Novartis, Baxter, CSL and Solvay.

WHO Director-General Margaret Chan has said the H1N1 virus is stable and there were no signs of it mixing with other more dangerous types of influenza such as the deadly H5N1 bird flu strain.

At present, patients with mild symptoms generally do not need any medicines to recover, and Chan has stressed hospital visits are not necessary unless those infected with flu have certain warning signs.

These include long-lasting high fever in adults and a lack of alertness in children. Pregnant women and people with health problems including diabetes are also vulnerable to more severe effects from the new flu strain.

FAST-TRACK APPROVAL 'SAFE'

The WHO said vaccines had to be available quickly and in large quantities to have the greatest impact and it insists that fast-track approval will not jeopardise safety.

Vaccines arrived too late in the 1957 and 1968 flu pandemics to be of much use, and flu vaccines had not been developed in the 1918 "Spanish flu" pandemic which killed an estimated 50 million people.

Some concerns have been raised because of serious side effects and 30 deaths seen during a US swine flu vaccination in 1976.

Kieny said vaccine production and purity levels had improved significantly since but safety issues could arise during a pandemic when a vaccine is administered on a mass scale, even if they did not show up in safety trials.

As a result, countries are being advised to conduct intensive monitoring as the vaccination campaign goes on.

What is swine flu?

Influenza A(H1N1) virus is a subtype of influenzavirus A and the most common cause of influenza (flu) in humans. Some strains of H1N1 are endemic in humans and cause a small fraction of all influenza-like illness and a large fraction of all seasonal influenza. H1N1 strains caused roughly half of all human flu infections in 2006.[1] Other strains of H1N1 are endemic in pigs (swine influenza) and in birds (avian influenza).

In June 2009, World Health Organization declared that flu due to a new strain of swine-origin H1N1 was responsible for the 2009 flu pandemic. This strain is commonly called "swine flu" by the public media.

In the 2009 flu pandemic, the virus isolated from patients in the United States was found to be made up of genetic elements from four different flu viruses – North American Mexican influenza, North American avian influenza, human influenza, and swine influenza virus typically found in Asia and Europe – "an unusually mongrelised mix of genetic sequences."This new strain appears to be a result of reassortment of human influenza and swine influenza viruses, in all four different strains of subtype H1N1.

Preliminary genetic characterization found that the hemagglutinin (HA) gene was similar to that of swine flu viruses present in U.S. pigs since 1999, but the neuraminidase (NA) and matrix protein (M) genes resembled versions present in European swine flu isolates. The six genes from American swine flu are themselves mixtures of swine flu, bird flu, and human flu viruses. While viruses with this genetic makeup had not previously been found to be circulating in humans or pigs, there is no formal national surveillance system to determine what viruses are circulating in pigs in the U.S.

On June 11, 2009, the WHO declared an H1N1 pandemic, moving the alert level to phase 6, marking the first global pandemic since the 1968 Hong Kong flu.

H1N1 Flu (Swine flu) Vaccine Reccomendations

Novel H1N1 Vaccination Recommendations

With the new H1N1 virus continuing to cause illness, hospitalizations and deaths in the US during the normally flu-free summer months and some uncertainty about what the upcoming flu season might bring, CDC's Advisory Committee on Immunization Practices has taken an important step in preparations for a voluntary novel H1N1 vaccination effort to counter a possibly severe upcoming flu season. On July 29, ACIP met to consider who should receive novel H1N1 vaccine when it becomes available.

Novel H1N1 Vaccine

Every flu season has the potential to cause a lot of illness, doctor’s visits, hospitalizations and deaths. CDC is concerned that the new H1N1 flu virus could result in a particularly severe flu season this year. Vaccines are the best tool we have to prevent influenza. CDC hopes that people will start to go out and get vaccinated against seasonal influenza as soon as vaccines become available at their doctor’s offices and in their communities (this may be as early as August for some). The seasonal flu vaccine is unlikely to provide protection against novel H1N1 influenza. However a novel H1N1 vaccine is currently in production and may be ready for the public in the fall. The novel H1N1 vaccine is not intended to replace the seasonal flu vaccine – it is intended to be used along-side seasonal flu vaccine.

CDC’s Advisory Committee on Immunization Practices (ACIP), a panel made up of medical and public health experts, met July 29, 2009, to make recommendations on who should receive the new H1N1 vaccine when it becomes available. While some issues are still unknown, such as how severe the virus will be during the fall and winter months, the ACIP considered several factors, including current disease patterns, populations most at-risk for severe illness based on current trends in illness, hospitalizations and deaths, how much vaccine is expected to be available, and the timing of vaccine availability.

The groups recommended to receive the novel H1N1 influenza vaccine include:

Pregnant women because they are at higher risk of complications and can potentially provide protection to infants who cannot be vaccinated;

Household contacts and caregivers for children younger than 6 months of age because younger infants are at higher risk of influenza-related complications and cannot be vaccinated. Vaccination of those in close contact with infants less than 6 months old might help protect infants by “cocooning” them from the virus;

Healthcare and emergency medical services personnel because infections among healthcare workers have been reported and this can be a potential source of infection for vulnerable patients. Also, increased absenteeism in this population could reduce healthcare system capacity;

All people from 6 months through 24 years of age

Children from 6 months through 18 years of age because we have seen many cases of novel H1N1 influenza in children and they are in close contact with each other in school and day care settings, which increases the likelihood of disease spread, and

Young adults 19 through 24 years of age because we have seen many cases of novel H1N1 influenza in these healthy young adults and they often live, work, and study in close proximity, and they are a frequently mobile population; and,

Persons aged 25 through 64 years who have health conditions associated with higher risk of medical complications from influenza.

We do not expect that there will be a shortage of novel H1N1 vaccine, but flu vaccine availability and demand can be unpredictable and there is some possibility that initially, the vaccine will be available in limited quantities. So, the ACIP also made recommendations regarding which people within the groups listed above should be prioritized if the vaccine is initially available in extremely limited quantities. For more information see the CDC press release CDC Advisors Make Recommendations for Use of Vaccine Against Novel H1N1.

Once the demand for vaccine for the prioritized groups has been met at the local level, programs and providers should also begin vaccinating everyone from the ages of 25 through 64 years. Current studies indicate that the risk for infection among persons age 65 or older is less than the risk for younger age groups. However, once vaccine demand among younger age groups has been met, programs and providers should offer vaccination to people 65 or older.