Healthy Skepticism Library item: 20126

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Publication type: Magazine

Jennings L
Justification easy for influenza campaign
New Zealand Doctor 2001 Apr 118

Full text:

I am writing this viewpoint on behalf of the National Influenza Immunisation Strategy Group in response to Robyn Beckingsale’s practice nurse column “Campaign to reduce flu poses practice queries” (28 February 2001).

We would like to take the opportunity to answer some of the issues Robyn has raised regarding the National Influenza Awareness Campaign.

“So what makes the Ministry of Health and vaccine manufacturers think we would be interested in the annual influenza campaign”.

The influenza campaign has a direct impact on the health of the “at-risk” patient’s nurses care for within their practice. Nurses are most often the very people whom their patients ask about influenza vaccination. The information and answers that nurses give will have a huge impact on the choice their patients make in regard to influenza vaccination.

“I believe that practice nurses should always question why they do things, the bottom line being: is this in the best interest of patients?”

Nurses should question why they do things, and in doing so will need to update their own information to be able to answer their patients concerns and questions honestly and effictively.

Influenza has a large impact on our communities. On average 2.7 percent of the population attend a GP because of an influenza-like illness during the influenza season, and there are 278 hospital admissions and 34 fatalities a year directly attributable to influenza, although the true impact is much higher. 1 The risk of complications from influenza is much greater for those with underlying chronic disease.

“I am uncertain as to vaccinating all patients over 65 years, no matter what their degree of health”.

Serious complications following influenza are far more likely in the elderly, regardless of whether they appear fit and healthy or not. For example, the rate of chest complications following influenza has been estimated at 9.5 percent of the general population, but in those over 70 it can be as high as 73 percent. Over the last 10 years in New Zealand, 21.5 percent of hospitalisations for influenza occurred among older people, and approximately 94 percent of deaths attributed to influenza occur among person aged 65 years or more.

“It must be a good ploy for the manufacturers to persuade everyone over 65 into into having an annual flu vaccination”.

This is a Ministry of Health recommendation – not a manufacturer’s ploy. The Ministry of Health makes recommendations on expert advice and these recommendations are in line with those of other countries with influenza vaccination programs. An open, tendering process is used by the ministry to select the vaccine supplier.

“We have patients over 65 years who will never have another flu vaccination because they felt so unwell after it and/or they got the flu in spite of it”.

The possible side effects following influenza vaccination are widely misunderstood. It is important to be aware of the following points:

*Influenza vaccine cannot give you influenza! Inactivated influenza vaccine contains non-infectious killed viruses.

*Influenza vaccination is carried out during the autumn months leading up to the influenza season when a number of other respiratory viruses are circulating in the community. Coincidental respiratory diseases unrelated to influenza vaccination can occur after vaccination.

*Local reactions at the site of injection are common, are generally mild and rarely interfere with normal activities. Soreness at the site in injection may affect between 10 and 64 percent of patients and last for up to two days.

Fever, malaise, myalgia and other systemic symptoms can occur following vaccination most often affect persons with no previous exposure to the influenza virus antigens in the vaccine, especially children. Placebo-controlled trials suggest that, among the elderly and health adults, inactivated influenza vaccination is not associated with higher rates of systemic symptoms when compared to placebo injections.

It is important that any unexpected reaction to this vaccine be reported to CARM. However, it is equally important that the healthcare provider be aware of the “expected responses” to the vaccine.

“Surely the pamphlet refers to children who have chronic disease or who are immuno-compromised (being offered influenza vaccination).”

Yes that is right. While children bear the brunt of any influenza epidemic, and are the spreaders in the community, influenza is not usually a life-threatening condition for them. The current strategy is to protect children (aged six months and older), who have an ongoing medical condition, which will put them at risk of complications – the same as adults with at-risk conditions.

“Someone might like to tell me if a dose of the flu is more immunogenic than the vaccine for a health person”.

Both infection with an influenza virus and vaccination produce good protection against influenza. Influenza vaccine will prevent illness in 70-90 percent of health persons aged <65 years when the antigenic match between the vaccine and circulating viruses is close.

“Why didn’t we get the UK epidemic here?”

The reasons why New Zealand did not experience a severe A/Sydney/7/97 (H3N3) during the 2000 influenza season relate to our previous experience with this and other strains. The A/Sydney/7/97 (H3N3) virus was first identified in Sydney in July 1997 and soon after in Auckland. Since this time A/Sydney has circulated every winter causing the characteristic outbreaks of influenza throughout New Zealand. The consequent high level of immunity to this virus in our community probably restricted into circulated during the 200 influenza season. Further, the dominant virus during the 2000 season was A/New Caledonia/10/99 (H1N1), a virus normally associated with less severe outbreaks of influenza.

“Did people in the UK get the flu in such numbers because the immunisation didn’t work?”

The UK influenza epidemic early in 2000 related to the circulation of the A/Sydney/7/97 (H3N3) virus in a largely susceptible population. H3N3 viruses are characteristically associated with severe outbreaks and epidemics of influenza. The level of vaccine coverage in any country at the present time is not high enough to control the spread if influenza, and is not a reason for their severe outbreak.

“Was this a case of antigenic drift, which they couldn’t catch up with?”

The WHO coordinates a network of national virus laboratories in 80 countries worldwide and four Influenza Collaborating Centres. The collaborating centres are responsible for conducting detailed antigenic analyses of influenza virus can be rapidly identified. Surprisingly, the A/Sydney virus which affected the UK early in 2000, has undergone little change since 1997.

“How soon after a new strain of flu appears can they make a new vaccine?”

The WHO convenes, two meetings each year, one in February to determine the formulation of vaccines for the following Northern Hemisphere influenza season and one in October for the following Southern Hemisphere influenza season. Following this process, it takes about four months before the vaccine is available for distribution.

“If there is serious antigenic drift this year that may come to New Zealand, can the vaccine be made in time?”

It would take between four and six months for a vaccine to be available; however, specific influenza antivirals are now available for the treatment of influenza, and should be considered for those at greatest risk, in this situation.

Finally, Robyn can take heart in that the Ministry of Health is spending money on ensuring there are more resources, information and education about influenza, it’s prevention, as well as treatment. There is also a commitment to increase the public awareness of influenza and its seriousness – especially to those at greatest risk.

The National Influenza Immunisation Strategy Group (NIISG) undertakes this nation role. Local immunisation coordinators throughout New Zealand can be contacted for more in depth information, resources.

Within general practices every vaccinator has access to a copy of the INFLUENZA KIT, put out my GSK, the contract supplier of the free influenza vaccine.

This kit contains information and answers to many of the questions raised by Robyn, as well as where to go for more detailed information. It is endorsed by NIISG.

There are still many myths and lack understanding about influenza; its seriousness and the role of vaccination. GPs and practice nurses should not hesitate to contact the national influenza coordinator Lyn Smith at 03-313 7880.

1. Jennings L etal. Influenza surveillance and immunisation in New Zealand, 1990-1999. NZ Public Health Report 2001; 8: 9-12