By Dr MILTON LUM Watchful vigilance is needed to handle Influenza A (H1N1).
THE Director General of the World Health Organization (WHO), Dr Margaret Chan, announced on June 11, 2009 that the flu pandemic level was to be raised to level 6, which is the highest possible. This means that there is sustained human to human transmission of influenza A (H1N1) with community outbreaks in at least one country in two WHO regions. It meant that it was no longer possible to contain the virus to a particular geographical area.
During previous pandemics, the influenza virus took more than six months to spread as widely as the influenza A (H1N1) has spread in less than six weeks since the detection of the initial cases in Mexico and the United States.
International travel has contributed very significantly to the spread of the virus, seeding urban areas with an increased intensity of transmission.
As at July 1, 2009, health authorities in 116 countries have reported 77,201 cases and 332 deaths to WHO. As at July 2, 244 cases were reported in Malaysia, with no deaths. 206 patients had returned from abroad and 38 were due to local transmission.
This article was written with the objective of getting all readers on board the prevention train as everyone can take individual preventive measures that would collectively contribute significantly to controlling the spread of the disease.
InfluenzaInfluenza is a common infection that affects many people. It is caused by RNA viruses of the orthomyxoviridae family. The influenza viruses are classified into types A, B and C based on their core proteins.
Type A viruses infect humans and many other mammals, eg pigs and horses, as well as birds. Type B and C viruses usually affect humans.
Types A and B viruses are common causes of acute respiratory infections.
The virus often mutates. Minor mutations (antigenic drift) are frequent and cause repeated outbreaks. Major mutations (antigenic shift) are rare and are due to reassortment of genetic material from different A sub-types. When they occur, pandemics may arise, causing many deaths. The type B virus does not exhibit antigenic shifts.
The frequent viral mutations lead to outbreaks annually. This is because the immunity from an infection does not provide full protection against another infection by an antigenic or genetic variant of the same sub-type A virus or type B virus.
Influenza is spread by droplets and aerosols from the respiratory secretions of infected persons. The virus usually infects the upper respiratory tract, ie the nose, throat and bronchi. It rarely infects the lungs. If an infected person coughs or sneezes and does not cover it, the droplets containing the virus can spread to about a metre (three feet) distance. This can be inhaled by anyone very close to the infected person.
If the infected person coughs or sneezes into his hands, the droplets containing the virus are easily transferred to surfaces touched by the person. Traces of the viruses may be found on items at home and work, eg door handles, hand rails, computer keyboards etc as they can survive for several hours on these surfaces. Should anyone touch these surfaces and then the face, the person can get the infection.
Symptoms develop between one to five days. A person can be infectious from the day before symptoms develop until seven days afterwards. The infection spreads rapidly, especially among those who are in crowded areas. The virus survives longer outside the body in cold and dry weather. As a result, epidemics in temperate countries usually occur in winter.
The clinical features of influenza include a sudden onset of high fever, muscle ache (myalgia), headache, non-productive cough, sore throat, and running nose. Most people recover within a week or two without requiring any treatment.
It is difficult to distinguish influenza from other respiratory infections. Laboratory tests will help in confirming the diagnosis. The collection of specimens for viral culture is critical to the provision of information about the circulating influenza subtypes and strains. This is needed for decisions on treatment and the formulation of vaccines for the subsequent year.
Secondary bacterial pneumonias are a common complication, especially in children below two years, senior citizens and those with medical conditions, eg lung diseases, diabetes, cancer, kidney or heart problems. Infections can also lead to death.
Influenza is an upper respiratory tract infection that lasts a few days in most people, and is usually treated symptomatically. The body gets rid of the virus in a few days. Antibiotics have no role in the treatment of people who are otherwise healthy. However, they are used to treat secondary bacterial complications.
Influenza A (H1N1)Influenza A (H1N1) contain some elements of a virus found in pigs. There is no evidence of it circulating in local pigs and scientists are investigating its origins. It has spread from humans to humans worldwide, leading to the declaration of a pandemic flu outbreak.
The novel influenza A(H1N1) virus spreads in exactly the same way as ordinary seasonal colds and influenza. The symptoms are the same as the ordinary seasonal flu although it may be more severe with more serious complications. The typical symptoms are sudden fever and cough. Other symptoms include headache, myalgia, pain in the joints and limbs, sore throat, running nose, sneezing, tiredness and loss of appetite.
It is different from the ordinary seasonal influenza because it is a new virus that appeared in humans and spread globally very rapidly. Since it a new virus, no one will have immunity to it and everyone is at risk of getting the infection. This includes healthy adults as well as older people, young children and those with existing medical conditions. It is likely that the current pandemic will affect more people and lead to more deaths than the ordinary seasonal flu.
Dr Margaret Chan of WHO states concisely: “Thanks to close monitoring, thorough investigations, and frank reporting from countries, we have some early snapshots depicting spread of the virus and the range of illness it can cause ... We know, too, that this early, patchy picture can change very quickly. The virus writes the rules and this one, like all influenza viruses, can change the rules, without rhyme or reason, at any time ... Finally, and perhaps of greatest concern, we do not know how this virus will behave under conditions typically found in the developing world. To date, the vast majority of cases have been detected and investigated in comparatively well-off countries.”
Pandemics
During an influenza epidemic in the developed world, between 5% and 15% of the population will be affected. Hospitalisation and deaths usually occur in senior citizens and those with medical conditions. It is estimated there are three to five million cases of severe illness and between 250,000 to 500,000 deaths annually worldwide. Most deaths associated with influenza in the developed world occur in those aged 65 years and above.
The type A virus is the main cause of epidemics and pandemics, eg the Spanish flu in 1918 which resulted in estimated deaths of 40 million worldwide. The accuracy of this figure is being debated as there was no laboratory confirmation simply because the influenza virus was discovered in 1933, years after the event. More recent pandemics, which occurred in 1957 (“Asian influenza”) and 1968 (“Hong Kong influenza”), caused significant morbidity and mortality worldwide.
All the pandemics in the 20th century were characterised by a series of multiple waves, each of which caused increased mortality for two to five years. There was a mild first wave during the summer in the 1918 pandemic, followed by two severe waves the following winter. The 1957 pandemic had three winter waves during the first five years. The 1968 pandemic had a mild first wave in Britain, followed by a severe second wave the following winter
WHO currently categorises the severity of the influenza A (H1N1) pandemic as moderate. This means that:
·Most people recover from infection without the need for medical care;
·The incidence of severe illness is similar to that seen during local ordinary seasonal influenza outbreaks, although higher levels have occurred in some local areas and institutions; and
·Most countries have been able to cope with the numbers seeking care, although there are stresses in some localities.
There is concern about the occurrence of serious cases and deaths in young people, including those who have been previously healthy and those with pre-existing medical conditions or pregnancy. There are still many gaps in knowledge about the virus.
As the pandemic has mainly affected the more developed countries to date, WHO anticipates that a bleaker picture will emerge as the virus spreads to areas with limited resources, poor healthcare, and a high prevalence of underlying medical problems.
There is increasing evidence in many countries that sporadic cases are arising without any apparent link to travel abroad or to other cases in the country. The possibility of the local epidemiology of the infection mirroring that of these countries cannot be discounted.
Many health authorities have used mathematical models in their planning. For example, the Department of Health of the United Kingdom, after taking into consideration that the total illness levels in previous pandemics was 25 to 35%, have based their plans on illness rates of 50%.
What every person can and should do
The most effective way of stopping or slowing the spread of many infectious diseases, including influenza A (H1N1), is the prevention of the spread of germs. There are several inexpensive practical measures that can be taken for protection of individuals and their families.
·Good hand hygiene – Regular washing of the hands with soap and water or the use of anti-germ hand rubs will help in protection against many germs, including influenza A (H1N1).
·Avoid touching the nose, mouth and eyes – When one touches anything that is contaminated with germs and follows that by touching of the nose, mouth or eyes, infections may be contracted.
·Practise respiratory etiquette – Covering the nose and mouth with tissues when sneezing or coughing can prevent the spread of infection to others. One should always carry tissues as sneezing or coughing is unpredictable. Used tissues should be disposed promptly and carefully, eg putting in a bin or flushing it away in the toilet.
·Avoid close contact – This reduces the chances of catching an infection from the sick who, in turn, will also protect others from getting infections.
·Stay home when sick – This will prevent the spread of infections to others. The sick should be cared for by designated caregivers with appropriate instructions from a healthcare provider.
·Social distancing refers to keeping an arm’s length distance from others and minimising social gatherings, eg closing of schools etc. The former is a useful habit to have. Compliance with the latter is vital if advised by the health authorities.
·Improve general health with physical activity, nutritious food, adequate sleep, cigarette smoking cessation and substance abuse avoidance. Healthy people have better immune systems and can withstand infections better.
·Clean household and office surfaces, eg door handles or knobs, tables etc regularly with soap and water or disinfectant as germs can survive for some time outside the human body and are spread when a contaminated surface is touched.
·Household ventilation – Keeping windows open allow sunlight to get in and air to circulate, both of which will reduce the survival times of germs outside the body.
Medical attentionIt is advisable for anyone who is sick to seek medical attention as soon as possible. Immediate medical attention should be sought by anyone with:
·Fever; and
·One or more of the following respiratory symptoms: cough, sore throat, myalgia, difficulty in breathing; and
·One or more of following: close contact with a person diagnosed as probable or confirmed case of influenza A (H1N1) or recent travel to an area or country reporting cases of confirmed influenza A (H1N1).
This will facilitate early diagnosis, treatment and implementation of preventive measures. Whenever there is doubt, it is prudent to seek medical attention early than to feel sorry later.
Sometimes a definitive diagnosis is not immediately possible. However, it is vital that medical advice be followed. There is no place for self medication.
Facemasks
Queries have been raised about the use of face masks. Surgical facemasks used by surgeons, nurses and other healthcare professionals reduce the risk of the transmission of viruses or bacteria from surgeons, nurses and other healthcare professionals to patients undergoing procedures, eg an operation.
Facemasks are also used by doctors, nurses and other healthcare professionals to reduce their risk of getting infections from patients when there is a risk of droplet transmission.
As far as the public is concerned, there are certain situations when facemasks may be of benefit i.e.
·Reduction of the risk of transmission of respiratory infections to others, eg people with colds or influenza when in contact with others; or
·Reduction of the risk of caregivers getting an infection from persons with cold or influenza.
The use of facemasks by healthy people not involved in the care of sick people is not recommended. There is no scientific evidence available currently to suggest that this is an effective preventive measure. Furthermore, there are many practical issues that need to be considered, viz:
·The choice of facemask is important as the quality and effectiveness is variable;
·Improperly worn facemasks may not provide any protection;
·Prolonged wearing of facemasks may be necessary as exposure to infectious persons is random and unpredictable;
·Facemask users may not pay attention to good hand hygiene practices which are effective in reducing the spread of respiratory infections like influenza;
·Failure to wash the hands after removal of a facemask or its reuse will render it ineffective and increase the risk of self-contamination;
·Those with respiratory infections may use a facemask to hide their symptoms and go out when they should be staying at home; and
·Proper disposal of the facemasks is important in order that others are not exposed to risk of infection.
Summary
The novel influenza A (H1N1) virus is in the early stages of a pandemic. The scale of the problems it can pose is uncertain. Yet action is required now when the severity of the threat is still moderate.
Any intervention will involve trade-offs between the social and economic costs and the uncertain probability of greater harm of a widespread outbreak. The uncertainty, urgency and the costs of intervention make the efforts to control this pandemic very challenging.
There is need for vigilance, not complacency or panic. Everyone has to play their part in the efforts to control the spread of the disease. Individual efforts may not be significant by themselves but the collective contributions will be substantial. The understanding and active participation of the public is crucial to controlling the spread of this new disease.
Dr Margaret Chan of WHO summarises it succinctly: “Influenza pandemics, whether moderate or severe, are remarkable events because of the almost universal susceptibility of the world’s population to infection. We are all in this together, and we will all get through this, together.”
Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organization the writer is associated with.
