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Thursday, 16 February 2012

A second wave of swine flue coming in tropical countries


Authors are_:
Professor Pranab Kumar Bhattacharya MD(cal Univ) FIC Path(Ind.), Professor and HOD Pathology Calcutta School of Tropical Medicine ,108 CR Avenue Kol-73 and Ex-Professor of Pathology, In charge of Histopathology unit, in charge- Cytogenetics, Blood Bank &VCCTC Institute of Post Graduate Medical Education & Research[IPGME&R] ,244a AJC Bose Road, Kolkata-20, W.B, India, 
Bhattacharya Upasana- Daughter of Prof PK Bhattacharya-Student
Bhattacharya Rupak Bsc(cal.Univ)) MSC, Bhattacharya Ritwik, B.Com(Cal.Univ) ), Rupsa Bhattacharya ; Soumayak Bhattacharya Msc HM of 7/51 Purbapalli,PO- Sodepur N-24 Parganas, Kol-110. W.B, , Mukherjee Dalia BA (hons) cal, Mukherjee Debasis Bsc(cal),  Oaidrila Mukherjee of Swamiji Road South Habra North 24 Parganas(n) W.B India
Please See published link of this article at


The 
WHO says that many countries in tropical regions (represented by Central America and tropical regions of Asia including India), will continue to see increasing or sustained high levels of influenza activity with some countries reporting moderate amount strains on their healthcare system. In temperate areas of the northern hemisphere (represented by North America, Europe, and Central Asia ,India), H1N1 influenza and respiratory disease activity remains though however low overall, with some countries and some provinces experiencing only localized or pocket outbreaks of the disease. In Japan, the level of influenza activity has passed the seasonal epidemic threshold, signaling a very early beginning to the annual influenza season. Pandemic H1N1 influenza virus continues to be the predominant circulating strain of influenza, both in the northern and southern hemisphere of world 1 Total laboratory confirmed cases reported up to 23rd August 2009 by H1N1 over 2,09,438 while death occurred in at Least 2185 cases (1.04%) globally as per WHO, while death confirmed by CDC were 522 by 15th august 2009. In India death occurred in more then 130 cases up to 31 st August 2009.The countries and overseas territories/communities that have newly reported their first pandemic (H1N1) 2009 confirmed case(s) since the last web update as of 23 August 2009 are: Cameroon, Madagascar, and Mozambique. 1
Region Cumulative total
as of 23 Aug 2009
Cases* Deaths
WHO Regional Office for Africa (AFRO) 3843 11
WHO Regional Office for the Americas (AMRO) 110113 1876
WHO Regional Office for the Eastern Mediterranean (EMRO) 3128 10
WHO Regional Office for Europe (EURO) Over 42,557 At least 85
WHO Regional Office for South-East Asia (SEARO) 15771 139
WHO Regional Office for the Western Pacific (WPRO) 34026 64
Total Over 209438 At Least 2185
*Given that countries are no longer required to test and report individual cases, the number of cases reported actually understates the real number of cases.
Too rapid spread
2009 influenza pandemic has spread internationally with an unprecedented speed. In past, in all flue pandemics, flu viruses had needed more than six months to spread as widely as the new H1N1 virus, which has spread in less than five or six weeks. It is due to that international air travel is far more common then in previous pandemic times
A second wave is coming _:
WHO is advising the countries in northern hemisphere of planet to get them prepared in their health care infrastructure for a second wave of H1N1 pandemic spread? Countries with tropical climates, where the pandemic virus arrived much later than elsewhere, like in India also need to be prepared for a gradual increasing number of cases. Evidence from multiple outbreak sites demonstrates that the H1N1 pandemic virus has rapidly established itself and is now the dominant influenza strain in most parts of the world particularly in USA. The pandemic will persist in the coming months as the virus continues to move through susceptible populations
The clinical picture of pandemic influenza is largely consistent across all countries. The overwhelming majority of patients continued to experience mild to moderate illness. Although the virus can cause very severe and fatal illness, also in young and healthy people, the number of such cases however remains small over all the world. However large numbers of people in all countries will remain susceptible to infection during the 2nd wave. Even if the current pattern of usually mild illness continues, the impact of the pandemic during 2nd wave is larger numbers of severely ill patients requiring more and more intensive care infrastructure are likely to be the most coming urgent burden on health services, creating pressures that could overwhelm intensive care units and possibly disrupt the provision of care for other diseases. The age groups affected by the pandemic are generally younger. Most higher risk population who will require probably hospitalization and will experience higher death rate are among certain subgroups like Obese people, those are suffering from asthma, COPD, T.B, diabetes, hypertension, people living under socio economic deprived conditions like poverty laden people[60% people in west Bengal provinces] of India and people having multiple health problems, with little access to basic health care. This is true for those most frequently infected, and especially so for those experiencing severe or fatal illness. To date, most severe cases and deaths have occurred in adults under the age of 50 years, with deaths in the elderly comparatively rare. This age distribution is in sharp contrast with seasonal influenza, where around 90% of severe and fatal cases occur in people 65 years of age or older. Perhaps most significantly, clinicians from around the world are reporting a very severe form of disease, also in young and otherwise healthy people, which is rarely seen during seasonal influenza infections. In these patients, the virus directly infects the deeper lung, causing severe respiratory failure. Saving these lives depends on highly specialized and demanding care in intensive care units, usually with long and costly stays.The second wave could worsen as larger numbers of people become infected. The Second wave may affect resulting in 1.8 million hospitalizations and 90 000 deaths only in USA One important hope and good news is that swine flue H1N1 virus is not yet became more virulent neither the virus has been mutated since appearing in Mexico in April 2009
HIV Patients are not however at risk
The 2009 influenza pandemic is the first to occur since the emergence of HIV/AIDS. Early data from two countries suggest that people co-infected with H1N1 and HIV are not at increased risk of severe or fatal illness, provided these patients are receiving antiretroviral therapy. In most of these patients, illness caused by H1N1 has been mild, with full recovery. On current estimates, around 33 million people are living with HIV/AIDS worldwide. Of these, WHO estimates that around 4 million were receiving antiretroviral therapy at the end of 2008.
What is with Osletamivir?
Anti-viral drugs Osletamivir are of questionable efficacy as per authors with some dangerous side effects like the ones reported in Japan people are, abusing of the regular flu vaccination, which is not useful for swine flu, used oseltamivir (Tamiflu) and zanamivir (Relenza) against people diagnosed with the virus. In India and in West Bengal provinces of India swine flue patients were treated with oseltamivir( Tamiflue) as per WHO guide line, only who were positive for viral DNAby RT PCR in their throat swab test in government tertiary care hospital setup. Mexico City,USA also used oseltamivir (Tamiflu) and zanamivir (Relenza) against people diagnosed with the virus.The Fact about Tamiflu [Oseltamivir] is that it may be able to delay the spread of the virus for a short period of time (but will not prevent it’s spread ultimately); that it can shorten the duration of the illness by about a day (but not the fact that it can save lives or even prevent serious complications of the flu); that it is “an unpleasant experience” to take with side effects ranging from nausea, vomiting, and hallucinations to serious, rare effects like Stevens-Johnson Syndrome and toxic epidermal necrolysis 4 . If the Tamiflue given permission to be open prescribed by General practitioners and if given permission for open sell in medicine shops, then a large proportion of patients by GPs then many will be there who will be offered this antivirals unnecessarily for a flue like illness with fever. Antiviral susceptibility testing has increased in several countries, confirming that pandemic H1N1 influenza virus remains sensitive to the antiviral oseltamivir, except for sporadic reports of oseltamivir resistant pandemic H1N1 virus detailed in the previous web update[3 cases till date]
Vaccine is the solution
The companies like CSL and Vaxine have both begun tests on their products swine flue vaccine. CSL carried tests on 240 healthy adult volunteers while Vaxine had 300O one group in the CSL trial got one dose, while a second group got two doses, on the basis that if just one does protects then there will be more vaccine to go round. In IndiaCIPLA is trying to get a vaccine against Swine flue H1N1 virus.
The first batch of vaccine for the influenza A/H1N1 2009 “swine flu” pandemic should be ready and licensed by October,2009,[1a] and the United Kingdom’s government has ordered enough vaccine for each person to receive two doses in their own country. However UK government has it’s prioritization plan already announced, and frontline healthcare workers will be among the first to be offered this vaccination. A questioner based study showed that the overall willingness to accept this pre-pandemic H5N1 vaccine was then only 28.4% in their first survey, conducted at WHO influenza pandemic alert phase 3. No significant changes in the level of willingness to accept pre-pandemic H5N1 vaccine were observed despite the escalation to alert phase 6. The willingness to accept pre-pandemic H1N1 vaccine was however 47.9% among healthcare workers when the WHO alert level was at phase 5. The most common reasons for an intention to accept were “wishes to be protected” and “following health authority’s advice.” The major barriers identified were fear of side effects and doubts about efficacy. More than half of the respondents thought nurses should be the first priority group to receive such swine flue vaccines. The strongest positive associating factors were history of seasonal influenza vaccination and perceived risk of contracting the infection. There remains other side also. A strong and growing opposition for swine flue vaccine growing. A survey published online this week in the BMJ found that just over half of 8500 healthcare workers in Hong Kong said they must not be vaccinated against swine flu because of strong fears of side effects and doubts about the vaccine’s effectiveness[ 2] And a survey by Israel’s ministry of health similarly found that at least 25% of the population is not willing to be vaccinated against swine flu2. Can we be sure that the new pandemic H1N1 vaccine will be as effective and safe as it is seasonal flu vaccines? The European Commission has already approved four “mock-up” vaccines developed by Baxter, GlaxoSmithKline, and Novartis on the basis of earlier immunogenicity and safety data generated with H5N1 virus strains particular concern for recipients may be the association of the 1976-77 swine flu vaccine with Guillain-BarrĂ© syndrome, with an attributable risk of around 12 cases per million vaccinations.3 This rare event has decreased greatly during the past 15 years (to around 0.7 reports/million vaccinations).[1a] More over swine flue virus may cause parkinsonism like bird flue H5N1,the virus can sneak into the brain via the peripheral nervous system and it may plays a role in killing dopamine neurons. But need not to be panic
The fear is unnecessary. However a randomised control trial is vital
How much vaccine is needed to cover the pandemic? If each shot of pandemic flu vaccine contains 15 micrograms of swine flue viral antigens — the dose used in seasonal flu — and no adjuvant, annual global capacity stands then at about 876 million doses, according to the WHO. But as virtually no one is immune to the virus, most experts said that each person will need two doses, immediately halving that capacity. Moreover, higher doses of antigen may be needed to get an adequate response, further reducing capacity. Using adjuvants would boost annual capacity — to more than two billion doses in some WHOprojections. But such a huge amount of doses vaccine preparation will take much time. By this time a second wave is expected though no of cases has already declined. A sharp rise in cases during the winter months is expected as a second wave. In India, already more then 140 persons died of the swine flue. Will not Indian people, Indian health care givers, those dealing with swine flue patients and their family members need vaccination? In India, priority of swine flue vaccine should be first for healthcare professionals, chronically ill people, and children under 5. However a survey study showed that the potential benefits of influenza vaccination for healthcare workers are threefold—personal protection, protection of patients, and reduction of absenteeism,
the current H1N1 (2009) pandemic influenza strain is co-circulating with a very similar seasonal A (H1N1) influenza virus in many countries, which may offer some cross-immunity via its more conserved internal proteins (e.g., the matrix and nucleoprotein) in individuals who have been recently infected naturally with this seasonal A (H1N1) virus
If there is any significant cross-immunity conferred by antibodies raised to these internal viral proteins, this may mitigate the future scale of any pandemic with this virus. So, the eventual spread of this novel influenza A (H1N1) virus may not be as widespread.
References
1] Pandemic (H1N1) 2009 – update 63 ;Weekly update Global Alert and Response (GAR) World Health Organization
1a ] Department of Health. Letter from office of David Nicholson chief executive of the NHS in England, 13 August 2009. www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/documents/digitalasset/dh_104309.pdf Editorials Should healthcare workers have the swine flu vaccine?Evidence from decades of seasonal vaccination suggests likely benefits and low risk of adverse events BMJ 2009;339:b3398
2] Zosia Kmietowicz News Opposition to swine flu vaccine seems to be growing worldwide : BMJ 2009;339:b3461
3] Breman JG, Hayner NS. Guillain-Barré syndrome and its relationship to swine influenza vaccination in Michigan, 1976-1977. Am J Epidemiol 1984;119:880-9.
4] Robert W Leckridge Questions about the swine flu strategy Rapid Responses published to feature article by Adrian O’Dowd A/H1N1 influenza update BMJ 2009; 339: b2977 on28 July 2009

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