Monday, November 30, 2009

1,300 Adverse Drug Reactions and Side Effects from Pandemrix H1N1 "Swine Flu" Vaccine in Sweden

Almost 3.4 million adult doses of Pandemrix have been delivered to Sweden as of November 17. According to data from the Swedish Institute for Infectious Disease Control (SMI), by November 15 approximately 1.9 million individuals in Sweden have been vaccinated. In total, the Medical Products Agency has received close to 1,000 adverse event reports from Health Care Professionals and about 1,300 reports from consumers. The reporting pattern is generally consistent with what has been seen from previous clinical trials, with the exception of allergic reactions.

Since the vaccination campaign began, the Medical Products Agency has continuously published summaries of adverse events reported with Pandemrix. The summaries focus on reports relating to unknown and suspected serious side effects while the known adverse events are reported only briefly. In addition, this summary specifically addresses allergic reactions, neurological reactions, reactions in children and in pregnant women.

It is important to stress the following:

  • The reports describe reactions that have occurred in close connection to when the vaccine was given.
  • The reaction can thus be caused by the vaccine, but can also be signs of illness the patient suffered from regardless of the vaccination.
  • Causality assessment can only be made after the report has been carefully assessed

Health Care reports

Almost 1000 reports have been received from Health Care Professionals. The majority of the adverse events reported are expected and known reactions such as injection site reactions and flu-like symptoms. Cases of nausea, abdominal pain, swollen lymph glands, palpitations, chest pain, rashes, insomnia, nightmares, eye irritation, and shingles have also been reported.

Comments on certain types of reactions:

Allergic reactions

In total, 296 reports of allergic reactions have been received from health care providers. These reactions have occurred in 246 patients shortly after vaccination with Pandemrix. In cases deemed serious, the patients needed treatment with antihistamines, adrenaline and cortisone and in some cases also supervision in emergency room/hospital. In all cases, the hypersensitivity reactions resolved completely within a short time.

Three cases of anaphylactic shock have been reported. In one case the patient had a known egg allergy; in the second case the patient was allergic to several foods, including nuts, but not to eggs; the third patient had no previous history of allergy reported.

Of the 246 patients reporting allergic reactions, 14 patients had egg allergy while 32 patients reported allergy to other substances such as pollen, grass, drugs, nuts, peanuts, fruit, fish or fur, etc.

Allergic reactions not previously seen in the clinical trials are now being reported as adverse reactions to Pandemrix. Similar allergic reactions have also been reported in other countries in Europe using Pandemrix.

Adverse reactions related to allergic reactions, reported by Health Care Professionals:

Reaction

Known allergy
(no of patients)

Serious reactions

Non serious reactions

Seriousness not assessed

Total no of reported reactions

Allergic reaction

12

15

26

6

47

Anaphylactic reaction

6

20

3

1

24

Anaphylactic shock

3

2


1

3

Angiooedema

2

9

12

1

22

Oedema in mouth and throat

6

10

9


19

Urticaria

3

8

33

4

45

Exanthema

2

3

26

5

34

Flushing

1

2

10


12

Itching

3

1

34

3

38

Astma - worsened

4

5

5


10

Dyspnoea

4

13

26

3

42

Total

46

88

184

24

296

Neurological reactions

A total of 287 neurologic adverse events have been reported of which 56 were assessed as serious. Many of these reactions may be part of an allergic reaction. 88 of the events represent dizziness and fainting, while 66 describe paresthesia, or “tingling” or “pins and needles” sensations, occurring in one or several extremities or in the region of the lips, tongue or other parts of the face. Some reports indicate sensation of metallic taste. Most of these events occurred at the time of vaccination.

In 22 reports, “numbness”, “loss of sensation”, or “burning sensation” are described. Locations of such symptoms were noted in arms, with extension to hand and fingers; legs and feet; face; and occasionally the entire side of body. In a smaller number of patients, these symptoms were accompanied with motor weakness. These events have occurred from 45 minutes to 5 days after vaccination.

In addition, there have been seven cases of visual disturbances, such as "blurred vision" and “floaters”, which occurred 1-2 days after vaccination. Most of these cases were associated with fever, chills and headache and the vision changes were short-lived.

Facial palsy or similar symptoms have been reported in 7 patients aged 4-43 years. The number of reported cases is below what would normally be expected in a population the size of the now vaccinated.

Three cases of stroke are reported, one of them fatal. None of these cases is considered to have a casual association with the vaccination.

Reactions in children

As of November 15, at least 26 000 children younger than 3 years, and at least 430 000 children aged 3 years up to 13 years, have been vaccinated in Sweden. This estimate is based on data from the Swedish Institute for Infectious Disease Control (SMI). Since November 12, the recommendation in Sweden has been to vaccinate all children between 6 months and 3 years (i.e. also including children that do not belong to any risk group).

Through November 20, twenty eight reports with serious reactions have been received from health care professionals. Two of these cases occurred in children under 3 years, 10 cases in children aged 3-9 years and 16 cases between 10-17 years. Adverse events assessed as non-serious were reported for 7 children less than 3 years, 42 cases in children aged 3-9 years and 45 cases of children between 10-17 years.

The two serious cases reported in children less than 3 years were:

  • A girl who the day after vaccination was vomiting up to 20 times/day and was hospitalised. The girl is fully recovered.
  • A boy with insulin treated diabetes who two days after the vaccination was unresponsive and his blood sugar level was low. The boy is fully recovered.

The table below shows the reported serious adverse reactions in children divided in three age groups.

Serious adverse reactions in children, reported by Health Care Professionals:

Reactions

0-2 years

3-9 years

10-17 years

Total no of
reported
serious reactions

Myocarditis



1

1

Vomiting

1

1


2

Flatulence


1


1

Chest pain



1

1

Influenza like illness



1

1

Pyrexia



1

1

Anaphylactic reaction


2

1

3

Anaphylactic shock



1

1

Hypersensitivity



4

4

Meningitis



1

1

Body temperature increased



1

1

C-reactive protein increased



1

1

Convulsions


3

2

5

Facial palsy


1

1

2

Headache



1

1

Muscle contractions involuntary



1

1

Petit mal epilepsy

1

1


2

Syncope


1

1

2

Dyspnoea


1

2

3

Respiratory disorder



1

1

Urticaria


2

2

4

Flushing



1

1

Total

2

13

25

40


Reactions in pregnant women

As of now, based on data from the Swedish Institute for Infectious Disease Control (SMI), at least 31 000 pregnant women are vaccinated with Pandemrix.

Adverse reactions in pregnant women, reported by Health Care Professionals:


Reaction

Serious reactions

Non-serious reactions

Total no of reported reactions

Muscle aches


2

2

Fever, common cold


1

1

Facial palsy

1


1

Urticaria


1

1

Breathing difficulties


1

1

Palpitations

1


1

Abdominal pain, increasing liver enzymes, thrombocytopenia

1


1

False labour

1


1

Spontaneous abortion

4


4

Intrauterin foetal death

1


1

Total

9

5

14

In 4 women spontaneous abortions have occurred in temporal association with vaccination. In yet another woman, intrauterine foetal death (gestational age week 24) occurred two days after vaccination. In none of these cases a casual association between the vaccination and the event could be established.

Deaths reported

As of November 20, a total of 12 deaths have been reported, of which 4 are new reports since the previous summary published November 12.

Summary of ADR reports in Sweden with Pandemrix (received up to November 10) (2009-11-12)

Three of the four new cases involve elderly patients (79, 92 and 94 years) with concomitant chronic disease. The time between vaccination and death has varied between 2-13 days. In one case the autopsy report shows a previous major myocardial infarction and acute heart failure. For the second case autopsy is requested and additional information awaited. Autopsy has not been performed in the third case. From what has emerged so far, there is nothing to confirm a causal association between the vaccination and the deaths in these three cases.

The fourth new fatal case concerns a 67-year-old man who underwent a heart transplant 19 years ago and 13 days after vaccination had a transplant rejection reaction. It is possible that the rejection was influenced by the vaccination, since the rapporteur suspects incomplete treatment of the patient's underlying disease. This case is being further investigated.

Experience from consumer reporting

Since the vaccination campaign with Pandemrix began in Sweden on October 12, about 1300 consumer reports of suspected adverse reactions have been received by the Medical Products Agency. A large majority of the reported adverse events are judged to be non-serious. Since the previous summary published November 12, eighteen consumer reports with serious reactions have been received. Of these reports 5 concern allergic/anaphylactic reactions and six concern influenza like illness.

Among the other serious reactions are reports of abdominal pain, pneumonia and shingles. The reported non-serious reactions are mainly flu-like symptoms (including isolated headache or diarrhea), injection site reactions, and various forms of allergic symptoms.

No deaths are reported by consumers during this period. Reactions in children and pregnant women relate primarily to previously known or anticipated adverse events with this vaccine.

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