Tag Archives: Influenza

Influenza cases finally dropping- an update

The past few weeks are finally beginning to show a declining trend in the number of cases with influenza like illness (ILI) presenting to the ER . The last wave appears to have peaked the week of Oct 12-18 when we saw about 17% of visits to the ER having an ILI. The week of Nov 9-15 had 6% of visits with ILI. This week may be even lower. This is a welcome relief from the peak levels of mid Oct.

Nationally the same declining trend appears to be taking place with fewer states reporting active H1N1.

Does this mean that the season is over or that vaccination is not necessary? The answer is no to both.

Influenza does come in “waves”. We had a wave over spring break and another in Oct. We may get another wave in the next month or so. Having enough herd immunity through vaccination can minimize the wave by decreasing the number of susceptible individuals in the community. Remember the vaccination is of greater benefit for the community than for the individual. We all go a long way in protecting those who cannot protect themselves. So those who have not gotten their vaccinations should still do so.

On a side note; We are continuing to have intensive care hospitalizations due to influenza related complications. This week we have two otherwise healthy individuals between the ages of 45-50 with severe pneumonia related complication in the ICU. Both cases have been ill for over a month before seeking medical help. Both would have been infected during the last wave of influenza. Neither of them were vaccinated.

Remember even though the wave may have past. There are still people that may still be suffering from delayed complications.

Influenza activity Aug 30 to Oct 31 2009- a summary

Updates from the CDC show.

1. H1N1-2009 is the dominant influenza in circulation
2. Most isolates appear to be sensitive to Oseltamivir (tamiflu)
3. Outpatient visits for influenza like illnesses is higher than expected for this time of year (7.7% instead of 2.3%)
4. 672 deaths occurred due to lab confirmed H1N1 related illness in this time frame.

What is the effectiveness of seasonal influenza vaccination in preventing H1N1?

Data published from the CDC suggests that the seasonal vaccine is about 10% effective against H1N1, further underlining the need for specific 2009-H1N1 specific vaccination for this season.

In our local community the public response to vaccine clinics has been very good. We hope to increase the vaccination rate as the supply of vaccine improves in the coming week.

What about the risk of Guillain barre syndrome?

What Gullian barre? Guillain barre sydrome is a neurologic condition where the body immune systems antibodies misrecognizes parts of the nervous system as foreign and attacks it. The host can develop muscle weakness and even paralysis. This can be a serious condition. Fortunately it is very rare. This is NOT caused directly by a vaccine but by the immune system itself. This can therefore happen with anything that stimulates the immune system to produce more antibodies. In other words infection itself can produce GBS. Most GBS is caused by viral infections and by a common bacteria that causes food poisoning called Campylobacter.

There are about 10-20 cases of GBS per million population in any given year, this is known as the “background rate” of occurrence. This has been closely watched since the initial cases of GBS were reported in the 1970s and does not appear to have changed that much with subsequent influenza seasons. (Roper AH. The Guillain barre syndrome. N Engl J Med 1992 326:1130-6)

The first series of GBS related to vaccination was reported in JAMA in 1980. This was based on data collected from the 1976 influenza vaccination season where it was believed that people were getting GBS from the vaccination. In this study they cite an attributable risk of 13 cases of GBS per 100,000 population vaccinated (an alarmingly high number) based on a collection of 32 cases with a history of vaccination. They needed a background rate for comparison. Due to the lack of public health records for GBS at that time they called local neurologists on the roster of the local medical associations in the state of Ohio and asked them about all the cases they had seen in the studied time interval. With this information they arrived at a background prevalence of 2.6 cases per 100,000. Of course this data was met with appropriate alarm, it turned out to be a public relations fiasco.

More detailed studies of the initial finding were later published regarding the 1976 swine flu vaccination where 40 million people were vaccinated and possible 532 cases of Guillian Barre were reported and 32 people died. This gives a rate of
about 13 cases per million. One tenth the number originally cited in the smaller study and a number more in the middle of the expected background rate. Definitely less alarming.

Data collected prospectively in subsequent years have failed to demonstrate any increased risk.

The risk from vaccination therefore may add an additional risk of perhaps up to 1 additional case per 1,000,000 administered doses of influenza vaccine this is a very small number compared with the original 130 cases per 1,000,000 that was reported in the 1980 article. This is rare enough to go so far as to say that there is probably no causal relationship influenza vaccination and GBS.

How fast does the vaccine work?

“I got sick the day after I got vaccinated, the vaccine does not work!” is a common statement of alarm that frequently comes to me. Please understand that this is neither a failure of the vaccine nor caused be the vaccination itself.

Remember that the vaccine itself does not kill influenza. The vaccine stimulates your immune system to be ready for influenza if it were to encounter it in the future. This preparation or training takes about 2 to 4 weeks. Therefore there is some potential to get the “real” illness early after vaccination, though even that should be milder than if one was not vaccinated.

So if someone at home gets ill in the days after you got your vaccination, do not blame the vaccine. We are in the depths of flu season it is more likely than not that little johnny got infected at school than from your dead vaccination.

H1N1 status update- Spike in outpatient visits, good match between H1N1 vaccine and circulating virus

There are more cases of influenza like illness this year than expected. Also the number of deaths are higher than expected for this time of year. 69% of the 12,900 samples sent to the reference labs are positive for 2009 H1N1. Remember that most of these samples are from persons ill enough to be hospitalized. This does not report all infected cases as ambulatory persons are not being screened due to overwhelming demand for tests. The vast majority of cases probably do not need hospitalization. Therefore the number of cases of H1N1 likely to be much higher.

Almost all isolates of 2009 H1N1 are showing a good match to the current vaccine. Remember that the virus does tend to have high mutation rate making 100% coverage difficult.

For the most part H1N1 is showing susceptibility to Oseltamivir (Tamiflu).

Total number of pediatric deaths is now 95 cases nation wide for 2009 H1N1.

See the graph showing the unusual spike in outpatient visits for influenza like illness towards the right of the graph.

Remember to get your vaccination.

CDC data

Did I get vaccinated?

I did get my H1N1 2009 live attenuated intranasal vaccination on 10/22/09. It was really no big deal, took less than 5 minutes to do. I feel fine today.
I also took the inactivated injectable seasonal vaccination on 10/14/2009. I also vaccinated my family with the same formulation that night. Aside from some arm soreness that my 9 year old complained of, no one has had any complaints.

Pregnancy and antiviral treatment

Pregnant women are at higher risk of hospitalization and death from influenza.
Though Oseltamivir is category C due to lack of trials in this group, it has been used successfully in all stages of pregnancy.
All pregnant women with influenza like illness (ILI) should be started on oseltamivir as early as possible.
Do not wait for lab confirmation before initiating treatment.
If pregnant women is exposed to known case of influenza a 10 day course of oseltamivir may be indicated as prophylaxis.
Prevention with vaccination with inactivated injectable vaccine is indicated in all pregnant women.
CDC reference for details

Antiviral medications- indications

Most patients presenting to physician offices and emergency rooms with an influenza like illness (ILI) will not require antiviral treatment with Tamiflu (Oseltamivir).

The following groups have indications for treatment with antiviral agents
1. Early treatment with Oseltamivir is recommended for all hospitalized patients with suspected or confirmed ILI.

2. Patients with ILI and suspected lower respiratory tract illness, regardless of age or underlying conditions

3. The following should be treated with oseltamivir if presenting with an ILI even if not hospitalized
a. Symptomatic children <2 yrs of age
b. Symptomatic adults over the age of 65
c. Symptomatic pregnant women
d. Symptomatic persons with chronic diseases; asthma, cardiomyopathy, renal, hepatic, blood dyscrasias, diabetes. Also persons with ch neurologic conditions that may suffer with respiratory compromise such as seizures, spinal cord injuries, strokes.
e. symptomatic persons with long term immunosuppression including HIV

Latex allergies and vaccination

This issue was brought up today. A preprinted consent form at a local hospital has latex allergy listed as a contraindication for vaccination.

The facts:
The vaccine itself seasonal or H1N1 regardless of live attenuated intranasal or the injectable vaccine does not contain any latex.
It is only the top of the bottle on multi-dose vials of the injectable vaccine that does contain latex. This would therefore not recommended in those with latex allergies.
Persons with latex allergies can take single dose vaccines.
Link to package insert