Influenza on the increase in Norway

January 4, 2013, Norwegian Institute of Public Health

The 2012-2013 influenza season in Norway is emerging and above the epidemic threshold. The activity at the moment is of medium intensity. The three different influenza viruses that are circulating are all covered by the seasonal influenza vaccine. People with risk factors are advised to take the seasonal influenza vaccine. There are no changes in the risk groups. The situation is being continuously monitored and recommendations may change if required.
So far most confirmed cases are A (H1N1) (swine influenza) and influenza B viruses, with fewer A (H3N2), but the picture may change during the winter.

We expect that infection caused by A (H1N1) virus (swine influenza) could constitute a larger proportion of this winter's than in the last two winters, but that pre-existing immunity in the population will limit the epidemic's spread. This year we have a regular seasonal epidemic, not a . A pandemic requires a to which people do not have immunity, which is not the case this year.

" are unpredictable. The Norwegian Institute of Public Health is monitoring the situation closely with the means at our disposal. The number of people who become ill varies from year to year. The size of the epidemic is impossible to predict," says Karin Rønning, Director of the Department of Infectious Disease Surveillance, at the Norwegian Institute of Public Health.

It is expected that, as with any , some people will be admitted to hospital, including intensive care, and that some deaths will occur. This is not specifically caused by the A (H1N1) virus, but can happen as a result of any .

The risk of serious illness

For most people, influenza is a disease that passes without the need for medical attention.

People with are most vulnerable to severe illness, and it is rare for healthy people to develop serious complications from influenza. People with risk factors may also experience deterioration of their underlying disease following influenza. The risk groups apply for all types of influenza virus.

Life-threatening illness rarely occurs in healthy people. Death may also occur, but mainly among people who are at increased risk for severe illness.

People with risk factors should be vaccinated as soon as possible. The risk groups are:

  • people who are 65 years or older 
  • residents in sheltered housing and nursing homes 
  • pregnant women, especially in the 2nd and 3rd trimester 
  • adults and children with chronic respiratory diseases, particularly those with reduced lung capacity 
  • adults and children with chronic cardiovascular disease, especially those with severe heart failure, low cardiac output or pulmonary hypertension 
  • adults and children with impaired immunity against infection 
  • adults and children with diabetes mellitus (both type 1 and type 2) 
  • adults and children with chronic renal failure 
  • adults and children with chronic liver failure 
  • adults and children with chronic neurological disease or injury 
  • adults and children with very severe obesity, i.e. body mass index (BMI) over 40 kg/m2 
Vaccination is also recommended to health care personnel as they are more susceptible to infection from patients and risk infecting other patients if they are become ill.


Rare cases of life-threatening illness can occur with all the three circulating , but these have been somewhat more frequent in adolescents and young adults with A (H1N1) virus ().

Norwegians are generally well protected against A (H1N1) by the pandemic, because so many people either took the vaccine or became ill. However, the efficacy of the vaccine from 2009 is no longer sufficient for many people to prevent disease, and if you are in a risk group you should take the seasonal vaccine even if you had the pandemic vaccine.

Admission to hospital

Every year, influenza viruses cause outbreaks of influenza. During this period, the primary health service and hospitals receive a greater number of patients.

The Norwegian Institute of Public Health does not have a surveillance system of influenza-related hospital admissions. We want to establish this to give a better overview of severe illness from influenza.

Together with influenza, a number of other respiratory viruses (e.g. RS-virus) are circulating which present a similar clinical picture to influenza, leading to many hospital admissions. Many patients with poor lung function (COPD and asthma) are admitted to hospital, some due to influenza and others due to other circulating respiratory viruses.


Use of antiviral drugs may be considered, especially for the risk groups and where there is evidence of severe illness. Treatment should start within 48 hours of the onset of symptoms.

Vaccination autumn 2012

The vaccination coverage of risk groups is lower in Norway than in many other European countries, and is significantly lower than the target of 75 per cent recommended by the World Health Organization.

For the 2012-2013 season, the NIPH despatched 412,000 doses of seasonal to municipalities for use in risk groups. In addition, around 20,000 doses of vaccine were despatched for use in non-risk groups. As of 30th November 2012, other wholesalers had sold about 34,000 doses.

It is uncertain how many of the despatched doses have been administered. As of 30th December 2012, there were 62,892 registered influenza vaccinations in SYSVAK.

Informal reports from the municipal health service indicate that interest in the influenza vaccine has been low in autumn 2012. There is reason to believe that many municipalities still have available vaccine doses intended for the risk groups.

There is a shortage of available vaccines in Europe. The Norwegian Institute of Public Health is investigating the possibility of obtaining more vaccine for the 2012-2013 season.

Explore further: Reconstructed 1918 influenza virus has yielded key insights, scientists say

Related Stories

Reconstructed 1918 influenza virus has yielded key insights, scientists say

September 11, 2012
The genetic sequencing and reconstruction of the 1918 influenza virus that killed 50 million people worldwide have advanced scientists' understanding of influenza biology and yielded important information on how to prevent ...

FDA approves first 4-in-1 flu vaccine

February 29, 2012
Federal health officials have approved the first vaccine that protects against four strains of the common flu, offering one additional layer of protection against the influenza virus that affects millions each year.

Recommended for you

Creation of synthetic horsepox virus could lead to more effective smallpox vaccine

January 19, 2018
UAlberta researchers created a new synthetic virus that could lead to the development of a more effective vaccine against smallpox. The discovery demonstrates how techniques based on the use of synthetic DNA can be used to ...

Study ends debate over role of steroids in treating septic shock

January 19, 2018
The results from the largest ever study of septic shock could improve treatment for critically ill patients and save health systems worldwide hundreds of millions of dollars each year.

New approach could help curtail hospitalizations due to influenza infection

January 18, 2018
More than 700,000 Americans were hospitalized due to illnesses associated with the seasonal flu during the 2014-15 flu season, according to federal estimates. A radical new approach to vaccine development at UCLA may help ...

Zika virus damages placenta, which may explain malformed babies

January 18, 2018
Though the Zika virus is widely known for a recent outbreak that caused children to be born with microencephaly, or having a small head, and other malformations, scientists have struggled to explain how the virus affects ...

Certain flu virus mutations may compensate for fitness costs of other mutations

January 18, 2018
Seasonal flu viruses continually undergo mutations that help them evade the human immune system, but some of these mutations can reduce a virus's potency. According to new research published in PLOS Pathogens, certain mutations ...

Study reveals how MRSA infection compromises lymphatic function

January 17, 2018
Infections of the skin or other soft tissues with the hard-to-treat MRSA (methicillin-resistant Staphylococcus aureus) bacteria appear to permanently compromise the lymphatic system, which is crucial to immune system function. ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.