CF and H1N1 infection

Question

Hello
I have CF since I was born and I am nearly 27 years old. I was infected by the H1N1 virus at the end of 2009 and since then I experience more difficulties to expectorate.
Do you think that there is a relationship between the decline of my lung situation and the H1N1 infection ?
Thank you

Answer

Hello,
This is a good question.
It is has been known for a long time that viral respiratory infections can precipitate what is called an « exacerbation of the chronic bacterial bronchial infection » (also simply called « acute pulmonary exacerbation », or else « exacerbation ») in people suffering from cystic fibrosis (CF).
An « exacerbation » is characterised by increased respiratory symptoms: increased cough, new nocturnal cough, more and more coloured and more voluminous expectorations than seen usually, an increased breathlessness, and it can also come with general symptoms like malaise, fever, lack of appetite, etc. Exacerbations, concomitant and/or caused by viral infections can leave sequelaes in some CF patients (1).
A number of recent studies has investigated the incidence of viral respiratory infections in people with CF. In children, these studies showed that 2/3 of the children with an exacerbation, simultaneously presented a viral respiratory infection. Compared to the exacerbations without concomitant viral respiratory infections, the exacerbations with concomitant viral respiratory infections are statistically more common for the younger children and boys and tend to be more severe (2).
Viral respiratory infections are, thus, frequent in children, but also in adults. Indeed, another recent study, using classic methods to establish viral infection, but also modern molecular techniques, showed that a viral factor can be detected by 1/3 of the adults with acute pulmonary exacerbations (3). The influenza virus can cause acute degradations like all other respiratory viruses (RSV, adenovirus, rhinovirus, human metapneumovirus, …).

The impact of H1N1 infection on people with CF has been studied by an European consortium which sent out questionnaires to 25 CF reference centres situated in 10 different European countries. Right after the 2009 H1N1 pandemia, more than 4600 CF patients were being followed in one of those centres. A H1N1 infection has been documented for about a hundred patients aged 13 years old on average (1-39 years). The principal symptoms were fever and respiratory symptoms; half of the patients had to be hospitalized and had to be given intravenous antibiotics. Most of the patients recovered rapidly from the point of view of pulmonary function level and returned to their usual pulmonary function within a month after the infection. However, a few patients had to be admitted to the intensive care unit and had to be mechanically ventilated. Some of those patients died (4). Similar data can be found in other scientific reports: in most of the cases the H1N1 infection wasn't a severe infection and had just little consequences for the patient, however this wasn't the absolute rule, particularly patients who were already more affected on the pulmonary level were prone to have a more severe evolution and sequelaes. In my own experience, a few patients definitely sustained lung damage because of this infection and in a few a lung transplantation had to be considered (although before the infection transplantation was not required in these specific patients).

Currently, different questions are still unanswered: 1) is there a cause and effect relationship between a viral respiratory infection and an acute pulmonary exacerbation ? The logical answer would be « yes » but this is far from being established... 2) How does a viral respiratory infection lead to the multiplication of bacteria and to the exacerbation? At the moment there are only preliminary answers: the virus causes a lot of inflammation in the bronchial tree, the anti-viral response of CF patients could be altered... (5, 6). A certain number of research teams currently investigate these questions in order to bring more specific answers.
As you see I tried to give you a general answer: yes, the H1N1 infection has had a harmful and definitive impact on the medical situation of certain patients ; however I cannot pronounce myself on your personal case, which you should discuss with your doctor. For yours and your doctor 's information I have cited a number of relevant articles below.

Best wishes,
Christiane Knoop

1. Wang EE, Prober CG, Manson B, Corey M, Levison H. Association of respiratory viral infections with pulmonary deterioration in patients with cystic fibrosis. N Engl J Med. 1984 Dec 27;311(26):1653-8.
2.Asner S, Waters V, Solomon M, Yau Y, Richardson SE, Grasemann H, Gharabaghi F, Tran D. Role of respiratory viruses in pulmonary exacerbations in children with cystic fibrosis. J Cyst Fibros. 2012 Sep;11(5):433-9.
3. Hoek RA, Paats MS, Pas SD, Bakker M, Hoogsteden HC, Boucher CA, van der Eerden MM. Incidence of viral respiratory pathogens causing exacerbations in adult cystic fibrosis patients. Scand J Infect Dis. 2012 Sep 19.
4. Viviani L, Assael BM, Kerem E; ECFS (A) H1N1 study group. Impact of the A (H1N1) pandemic influenza (season 2009-2010) on patients with cystic fibrosis. J Cyst Fibros. 2011 Sep;10(5):370-6.
5. van Ewijk BE, van der Zalm MM, Wolfs TF, van der Ent CK. Viral respiratory infections in cystic fibrosis. J Cyst Fibros. 2005 Aug;4 Suppl 2:31-6.
6. Vareille M, Kieninger E, Alves MP, Kopf BS, Möller A, Geiser T, Johnston SL, Edwards MR, Regamey N. Impaired type I and type III interferon induction and rhinovirus control in human cystic fibrosis airway epithelial cells. Thorax. 2012 Jun;67(6):517-25.

24.01.2013