Tag Archives: H1N1

No increase in Gullain Barre incidence with H1N1 2009 vaccination-says CDC

The preliminary results from the last H1N1 2009 vaccination season are in. So far no excess cases have been reported with the vaccine when compared to previous vaccination years. More people developed Guillain Barre without vaccination than with the vaccine (total numbers). The rate of cases per 100,000 population were slightly greater in those with vaccination than those without vaccination (0.8 per 100,000 persons greater). These results are consistent with the expected safety profile as seen in previous years.

No statistically significant association between GBS and 2009 H1N1 vaccination has been seen

More information on the history of Guillain Barre and vaccinations

Preliminary Results: Surveillance for Guillain-Barré Syndrome After Receipt of Influenza A H1N1 2009 Monovalent Vaccine — United States, 2009–2010.

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.

Pregnancy and H1N1 vaccination

The question of vaccination for Influenza (H1N1) in pregnancy is frequently asked. A small study published by NIH does provide some answers around this.

Why all the concern about pregnancy?
To date there have been 100 pregnant women hospitalized with H1N1 in the US this season. 28 deaths have occurred in this group. This is an alarmingly high proportion for this healthy group (28% of admissions!). Though the total numbers seem very small it is the proportion of deaths in this important group that is high. Why is this group more important than other? To say the obvious; too many other lives depend on these women. A pregnant women is likely to have other children at home, those children are not only at risk for illness from mother but if mother is incapacitated or worse dies can changes the social structure of the home and future lives of her young children. Loss of life in other groups of people as traumatic as it may be does not carry as great a social burden as losses in this group can. This group is therefore at highest priority to be vaccinated.

Do pregnant women have adequate response to vaccination?
The study does show that pregnant women do mount an adequate response to a single dose of inactivated injectable vaccine and it is well tolerated. The 15mcgm dose appears to provide adequate response in 92% of recipients and 30mcgm in 96% of recipients. the pool sizes were very small at 25 women in each group.

The H1N1 2009 vaccine is made in an identical process to the existing seasonal influenza vaccine. It is a killed vaccine, therefore cannot cause H1N1. It is also thiomersal free.

Influenza vaccination at our hospitals

If there is one good thing that has come out of this flu season then it is the awareness of vaccination. In years past, on the average we have had 45% vaccine coverage for hospital employees. This has been abysmally low to offer any real herd immunity. This year with an aggressive proactive approach with formal lectures and informal face to face discussions with groups of hospital staff discussing the benefits, myths. We have a record >75% seasonal vaccine coverage. Most of the recipients were taking influenza vaccine for the first time. We may actually run out of seasonal vaccine for the first time.

With regards to H1N1, we did start with live attenuated intranasal last week and had a high acceptance rate among those who qualified. Unfortunately many of the motivated staff did not qualify. This week we did receive inactivated injectable vaccine. The acceptance rate for this has been very good. I did need to go on an education round in the hospital and answer more question. But once a few staff members got motivated more and more followed. I think we will have a good coverage for H1N1 too.

Some factors promoting better acceptance may be the larger numbers of 20-49 year olds that are coming to the hospital with moderate to severe viral pneumonia. A few have required intensive care management. The number of patients coming to the ER with influenza like illness (ILI) has seen a sharp spike in the past week. The proportion of ILI that are influenza A positive has gone up from 3-5% in the weeks of Oct 5th and 12th to 18% in the week of Oct 19th.

So far very few complaints about getting vaccinated aside from the minor injection site aches and pains.

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

Safety data on H1N1 vaccination

The New England Journal of Medicine published a study focusing on the safety profile of the H1N1 vaccine.

It was conducted in China where 2200 subjects received a dose of H1N1. 2103 (95.6%) received the second dose. They ranged in age from 3y to 77y the subjects were randomized to either vaccine or placebo. Patients were removed from the study once they achieved an increase in antibody titer of 4x baseline. Which is considered adequate protective levels. Those that did not achieve this level of antibody received a second dose at day 21.

The results did show good efficacy of the vaccine in adults with just a single dose. Children and the elderly did need the second vaccine dose to get the needed antibody level.

One adverse result was seen in the study, it was development of atrial fibrillation in a man who was receiving placebo. There were no serious adverse results in any of the vaccine recipients. Local pain at the injection site was the main complaint.

This is the New England Journal article: A Novel Influenza A (H1N1) Vaccine in Various Age Groups

Differences between intranasal live and inactivated injectable vaccine for influenza H1N1

Both vaccines are effective. They are manufactured with similar ingredients and both have chicken eggs in them.

Live intranasal vaccine
1. At least in children appears to provide 30-50% greater immune response.
2. Easy to administer- no needles
3. No evidence that transmission of live virus to contacts occurs. Still would recommend precautions if taking care of patient with recent bone marrow transplant.
4. Not approved for 49 years or pregnancy
5. Should be avoided if taking other live vaccines such as MMR, shingles vaccine at the same time
6. Inactivated vaccines can be given with it, such as seasonal influenza
7. Should avoid Tamiflu for 48 hours before and 2 weeks after vaccine

Inactivated injectable vaccine
1. Lower response rate
2. Needs injections
3. Better safety data in the over 49yrs and in pregnancy
4. Can be given ages 6 months and up
5. Can be given with other vaccines
6. Can be given to very immunocompromised patients
7. Tamiflu does not interfere with it

Vaccination for H1N1 and Tamiflu

Persons that are currently taking tamiflu can be vaccinated with inactivated injectable vaccine. This will not interfere with the response.
If you will be taking live intranasal vaccine. Tamiflu (oseltamivir) should not be taken for 2 days prior or 14 days after receiving the vaccine. The the Tamiflu will kill the virus in the vaccine and hence reduce the effectiveness.

2009 H1N1 vaccination- the low down

This is a summary of the CDC recommendation on H1N1 vaccination this year, I have added information to add some context to some of the recomendations.

Who should receive the 2009 H1N1 vaccination?

The goals of vaccination are to protect those at most risk of complications from disease, those who cannot be safely vaccinated and those who are at greatest risk of being a transmitter to other susceptible persons.

The groups that should be vaccinated therefore are:

1. Pregnant women – they have been seen to have higher rates of hospitalization and death. This group should only receive the inactivated injectable vaccine.

2. People who live with or take care of children younger than 6 months of age, as these young children are under the recommended age for vaccination and need a protective wall of immunized people around them. Remember the virus needs to spread from an infected person to be transmitted to a non-infected person. Therefore the best way to protect the very young is to only let immunized persons be in contact with them. These persons can receive live intranasal vaccine as long as they are healthy, not pregnant, and under the age of 50 years. All others will receive inactivated injectable vaccination.

3. Healthcare and emergency workers, this is not just to protect them but more importantly to protect their patients. Hospitals and clinics obviously attract patients with H1N1. Healthcare personell will have significant contact with them and if themselves become infected will transmit infection to their colleagues and more importantly other patients that they care for. Vaccinating all healthcare personell will significantly reduce transmission. Remember transmission starts about a day before the fever starts. Therefore damage may have already been done the day before you even get ill. Healthcare workers CAN receive either live or inactivated as long as they are under 50 years of age and are not pregnant and are not involved with bone marrow transplant units.

4. Persons between ages 6 months and 24 years- this group was over represented in the recent ICU admissions and deaths. This group can receive either live or inactivated vaccine as long as they are not pregnant and are healthy.

5. People ages 25-64 with chronic health issues. They will need inactivated vaccination.

Notice that the over 65 age group that is commonly vaccinated for seasonal influenza is NOT on the list.

What if there are shortages of vaccine? The groups that should be vaccinated first are pregnant women, those who live with or care for children under the age of 6 months, healthcare personnel with direct patient contact, children 6 months to 4 yrs and children 5 through 18 years with chronic medical conditions. Once these high risk groups are vaccinated then focus will be on persons ages 25-64 years.

For those ages 10 and above should receive one dose. Whereas children 9 years and under should receive two doses separated by a month. This is due to the lower immune response with a single dose to have adequate antibodies.

List of those NOT receiving live intranasal vaccine for H1N1
• People younger than 2 years of age; insufficient testing
• Pregnant women; insufficient testing in this group
• People 50 years of age and older; insufficient testing in this group
• People with a medical condition that places them at higher risk for complications from influenza, including those with chronic heart or lung disease, such as asthma or reactive airways disease; people with medical conditions such as diabetes or kidney failure; or people with illnesses that weaken the immune system, or who take medications that can weaken the immune system;
• Children younger than 5 years old with a history of recurrent wheezing;
• Children or adolescents receiving aspirin therapy;
• People who have had Guillain-Barré syndrome (GBS), a rare disorder of the nervous system, within 6 weeks of getting a flu vaccine, though this has never been shown to be causally related any more than getting the “wild type” infection, it is recommended as a precaution.
• People who have a severe allergy to chicken eggs or who are allergic to any of the nasal spray vaccine components. The vaccine including the live form is made with chicken eggs. Remember SEVERE allergy to eggs is the contraindication. Most individuals can take the vaccine if they can eat scrambled eggs or have cake made with eggs.

Regarding seasonal vaccination
It is still necessary for the usual groups– ages over 65 etc
It will not provide protection against H1N1
the list of individuals needing vaccination for seasonal influenza is as follows
Children aged 6 months up to their 19th birthday
Pregnant women
People 50 years of age and older
People of any age with certain chronic medical conditions
People who live in nursing homes and other long-term care facilities
Health care workers
Household contacts of persons at high risk for complications from the flu
Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated)
Note that there is considerable overlap between the seasonal and H1N1 list, many persons will need both vaccinations.

Can seasonal vaccine and H1N1 be given together?
Inactivated seasonal (TIV) and inactivated H1N1 along with pneumovax can be given together.
Live seasonal (LAIV) and inactivated H1N1 can be given together.
TIV and live H1N1 can be given together.
Do NOT give live intranasal seasonal (typo corrected: this was previously written as TIV) and live intranasal H1N1 together

What if I already had the flu this year?
Regardless of whether the illness was H1N1 or not, if you are in a risk group that should be vaccinated do get immunized.

Breast feeding and vaccination?
It is safe, including the live intranasal vaccination.

What about Tamiflu and vaccination?
Do not take Tamiflu for 2 weeks after live intranasal vaccine, it will kill the vaccine virus.
Do not get vaccinated for at least 48 hours after Tamiflu is discontinued.
Inactivated injectable vaccine can be given with Tamiflu. Continue reading