The H1N1 flu virus – commonly known as the swine flu – is a new strain of pandemic influenza which scientists have distinguished from the seasonal flu, to which humans have no natural immunity to protect against. Most healthy people recover from the flu without problems, but certain people are at high risk for serious complications.
Swine Flu and the 1918 Influenza Pandemic
According to the Public Health Agency of Canada, the H1N1 flu virus first became widespread in April 2009; however, swine were first noticed to suffer from influenza-like illnesses in 1918 during the human influenza pandemic – or worldwide infection – of that time. Swine influenza was not responsible for the 1918 human influenza pandemic, and the swine flu virus remained relatively unchanged until the 1990s, when for reasons unknown, swine influenza viruses diversified and new stains emerged.
Swine Flu Outbreaks in Humans
Before the swine flu pandemic of 2009, there was only one known swine flu outbreak in people which caused public health concerns. In 1979 there was a swine flu outbreak among soldiers at Fort Dix, New Jersey in the United States. During this outbreak, of more than 200 recruits who tested positive for the swine flu virus, one recruit died and 12 were hospitalized with influenza. The other soldiers were found to have had few or no influenza symptoms.
Since the infecting virus strain of 1979 was observed to be strongly related to the swine influenza virus, public health officials were concerned about the potential for a new pandemic and initiated a mass public vaccination in which up to 25 percent of the American public was vaccinated. Fortunately, the 1979 strain was not easily transmitted between humans; human cases outside Fort Dix were rare, and there was no epidemic.
1979 Swine Flu Mass Vaccination and Concerns About the Safety of the 2009 Swine Flu Vaccine
Some of the concerns today about the safety of vaccinations against the swine flu virus stem from the mass vaccination of 1979 in which the vaccine was associated with a small increased risk of Guillain-Barré syndrome – a serious neurological condition. For those concerned about today's H1N1 vaccine, it is important to note that the 1979 swine flu vaccine was made using an old-fashioned process which is no longer utilized.
Impact of the Swine Flu (H1N1) Pandemic
Since the initial cases of swine influenza discovered in April 2009 in Mexico, the disease has spread rapidly around the globe, and the World Health Organization (WHO) has officially declared the 2009 swine flu to be a pandemic.
Swine Flu Infection Rate
It is difficult for public health officials to determine exactly how many people have been infected with swine flu since not all people infected with H1N1 flu seek medical care, and not all people who seek medical care have specimens collected by their health care providers. However, the Centers for Disease Control and Prevention (CDC) estimates that more than one million people became ill with the swine flu during the first wave of the disease between April and June 2009 in the United States.
According to data collected by the CDC, from April 15, 2009 to July 24, 2009, a total of 43,771 confirmed and probable cases of swine flu infection were reported, and of these cases 5011 people were hospitalized and 302 people died. Since July 24, 2009, the CDC has discontinued counting confirmed and probable cases of swine flu infection. The CDC says that the reporting of individual cases was discontinued because as the novel H1N1 flu became more widespread, individual case counts became "an increasingly inaccurate representation of the true burden of the disease."
Deaths Caused by Swine H1N1 Influenza
As of late October 2009, the swine flu virus had been confirmed to have caused more than 1000 deaths in the United States and 95 deaths in Canada. Public health officials have emphasized that patients have had underlying health conditions in the vast majority swine flu infection cases which have resulted in death.
Effectiveness of the 2009 Swine H1N1 Vaccine
The CDC reports that as of late October, almost all of the influenza viruses identified so far are 2009 H1N1 influenza viruses which remain similar to the virus targeted by the H1N1 vaccine and remain susceptible to antiviral drugs with rare exception.
Sources:
http://www.emedicinehealth.com
http://www.phac-aspc.gc.ca
http://www.cdc.gov
http://www.hc-sc.gc.ca
http://www.who.int
Johneen Manning - My skills and interests are broad and varied – a consequence of the fact that in my early 20s I couldn't figure out what I wanted to ...
