ORIGINAL ARTICLE INFLUENZA A (H1N1) PANDEMIC: PAHANG EXPERIENCE Sapian M 1, Sahhir K 1, Rosnah I 1, Ardi A1, Rohida T 1, Azura M 1 & Zana Z 1 1 Pahang State Health Department ABSTRACT On 24 th April 2009 the World Health Organisation (WHO) announced Pandemic Influenza A (H1N1) alert phase 4 which was later raised to phase 6 on 11 th June 2009. By 11 th October 2009, 199 countries were affected with 399,232 laboratory confirmed cases resulting in 4735 death. In Pahang, the state and district operation rooms were activated on the 28 th April and 5 th May 2009 respectively to monitor surveillance, control and preventives measures carried out. This study was done to describe the situation of Pandemic Influenza A (H1N1) in Pahang from 28 th April 2009 till 10 th October 2009 in terms of laboratory confirmed cases and clusters reported, Influenza-Like Illness (ILI) surveillance, Severe Acute Respiratory Infection (sari) surveillance and health education activities. During the period, 490 laboratory confirmed Influenza A (H1N1) cases were registered with 5 deaths. The age ranges from less than 1 year to 76 years with median of 16 years old. 207 ILI clusters were recorded, 139 (67.5%) were Influenza A (H1N1) clusters. For surveillance activity, 11,570 (2.2%) of outpatient attendances were ILI cases while 966 (2.0 %) of total admissions were sari cases. There were 14,927 health education activities carried out during the period. The number of people affected by Pandemic Influenza A (H1N1) in Pahang reached its peak in mid August 2009 and later showed a downward trend. ILI surveillance was a useful tool to detect Influenza A (H1N1) activity in Pahang. Key words: Pandemic Influenza A (H1N1), Pahang, Influenza-Like Illness surveillance, clusters. INTRODUCTION Influenza virus is a common human pathogen that has caused serious respiratory illness and death over the past century. It has the potential to cause widespread pandemic. A pandemic occurs when a new type of influenza strain appears in the human population and then spreads easily from person to person. Reports of widespread transmission of the Influenza A (H1N1) virus in humans in Mexico, the United States and elsewhere have put the health authorities on a high alert 1. The emergence of a novel influenza A (H1N1) virus from Mexico in March 2009 2, and its rapid dissemination throughout the world has been the first international outbreak of public health concern since the new International Health Regulations came into effect in 2007, prompting the World Health Organization (WHO) and the international community to escalate their response in anticipation of a pandemic 3. On 24 th April 2009 the World Health Organisation (WHO) announced pandemic alert phase 4 Swine Influenza A (H1N1) which was later referred to as Influenza A(H1N1) due to the presence of mixed genes from North American swine, North American avian, North American human and Eurasian swine. The classical swine influenza lineage has evolved continuously since 1918, while the human lineage has caused many episodes of pandemics and endemics of influenza from 1918 to 1956. The human line apparently disappeared entirely around 1957 only to reappear in 1977, and has circulated endemically in human recently 4. Infections with swine influenza virus have been detected occasionally in humans since the 1950s and the resulting human disease is usually similar to human influenza viral infections. Complications, including pneumonia and death, have been reported in the literature in adults without underlying disease 5. WHO raised the pandemic alert level to phase 6 on 11 th June 2009 6. As of 11 th October 2009, 199 countries were affected; with 399,232 laboratories confirmed cases reported resulting in 4735 death 7. In anticipation for Pandemic Influenza, Ministry Of Health Malaysia has taken the lead in developing a comprehensive, multi-sectorial preparedness plan in 2006 which is known as National Influenza Pandemic Preparedness Plan (NIPPP). This plan provides a policy and strategic framework for a multi-sectorial response. State
of Pahang has adapted this plan with some modification to suit its needs. One of the essential components in this plan is the influenza surveillance system. It is the detection of Influenza-Like Illness (ILI) using sentinel general/primary medical practices able to detect increase of Influenza activities either epidemic or pandemic. Malaysia reported first imported case on 13 May 2009 followed by first local case on 15 June 2009. Pahang, one of the states in Malaysia reported first imported case on 14 June 2009 followed by first local case on 6 July 2009. An operation room for Pahang was initiated on 28 April 2009 to monitor and regulate Influenza A (H1N1) surveillance, prevention and control activities throughout the state. The study objectives are to determine the trend of reported Influenza A (H1N1) cases in Pahang, to describe the reported Influenza A (H1N1) cases by district, gender and age-group, to determine the occurrence of Influenza-Like Illness clusters by district, to describe the trend of ILI cases seen at government health clinics and sari cases among patients admitted in all hospitals and to outline the health promotion activities carried out during the pandemic period. MATERIALS AND METHODS This study is a cross-sectional situational analysis of cases and activities implemented at district and state level during the pandemic period from 28 th April 2009 until 10 th October 2009 in the state of Pahang. Data are analyzed and reviewed from various sources as mentioned below: Influenza A (H1N1) case register, ILI cluster register in Pahang State Operation Room. Daily returns of ILI patients seen at Out Patient Departments (OPD) from all government health clinics in Pahang. Daily returns of SARI patients seen at all government and private hospitals in Pahang. Daily returns on Health Education activities from districts in Pahang. For this study, the definitions used are as follows: Influenza A (H1N1) case is defined as an individual with laboratory confirmed Influenza A (H1N1) virus infection by real time RT-PCR 8,9. ILI is defined as a person with a sudden onset of fever 38 C and cough or sore throat, in the absence of other diagnosis 9. SARI is defined as a case that meets ILI case definition and shortness of breath and requiring hospital admission 9. Cluster is defined as two or more persons presenting with manifestations of unexplained acute respiratory illness with fever 38 C or who died of an unexplained respiratory illness and that are detected with onset of illness within a period of 14 days and in the same geographical area and/or are epidemiologically linked 8,9. RESULTS Incidence of Influenza A(H1N1) During the pandemic period, there were 490 laboratory confirmed cases reported in Pahang. The distribution of cases according to date of onset is as shown in Figure 1 below. The first case onset was on week 23 and the number of cases rose enormously from week 30 to week 33. During this peak period, 393 or 80.2% of total cases were reported. After this period, the number of cases showed a downward trend.
Figure 1. Number of cases by epidemiology week Influenza A (H1N1) case by district The cases were reported from all the 11 districts in Pahang. Almost more than half of the cases (50.2%) were from Kuantan district which is the capital city for Pahang. The distribution of cases according to district is as shown in Figure 2 below. There were also 5 deaths related to Influenza A (H1N1) in Pahang. These deaths occurred in Kuantan and Bentong district. Figure 2. Number of cases in Pahang by district (28 th April to 10 th October 2009) Influenza A (H1N1) case by gender As shown in Figure 3, 255 or 52.0% of cases were reported among males while the remaining 48% or 235 cases were among females.
Figure 3. Number of cases by gender Influenza A (H1N1) case by age The age of the cases ranges from below one year to 76 years old. 44.9% of the cases were among 15 to 29 years age group. Median age for cases reported was 16. See Figure 4 below. Figure 4. Number of cases by age group Influenza A (H1N1) Clusters Influenza A (H1N1) Clusters by district During the pandemic period, Pahang reported a total of 207 clusters of ILI. Out of this, 139 clusters or 67.2% were laboratory confirmed for Influenza A(H1N1). All districts in Pahang have reported episodes of clusters. 94.7% were from schools and higher learning institutions. 87 clusters (42.0%) were from Kuantan district. The distributions of these clusters are shown in Figure 5 below.
Figure 5. Influenza-Like Illness clusters in by district Influenza A (H1N1) Clusters by epidemiology week A total of 95% of the clusters were reported during week 30 to week 33 as in Figure 6 below. Surveillance of ILI and SARI Based on Figures 7 and 8 below, the number of ILI and sari cases reported showed an increasing Figure 6. Influenza A(H1N1) and ILI/URTI trend from week 30 and reached its peak on week 33 and then showed a decreasing trend.
clusters by epidemiology week Figure 7. Influenza-Like Illness (ILI) cases by epidemiolog week Figure 8. Severe Acute Respiratory Infection (sari) cases by epidemiology week Health Promotion Activities The summary of health promotion activities in Pahang is shown in Table 1 below.
Table 1. Influenza A (H1N1) health promotion activities HEALTH PROMOTION ACTIVITIES NUMBER OF ACTIVITIES Health Talks 1007 Exhibition 1685 Radio Talk / Announcement 943 Poster Distributed 12,409 Pamphlet Distributed 313,655 DISCUSSION In Pahang, only admitted ILI cases and few cases from each ILI cluster were laboratory tested for Influenza A (H1N1). So, the number of cases reported did not reflect the true number of Influenza A (H1N1) cases in Pahang. There was high possibility that the actual cases would be far greater. There were 490 confirmed Influenza A (H1N1) cases reported since the pandemic started until 10 th October 2009 in Pahang. It is estimated that the median multiplier of reported to estimated cases was 79; that is, every reported case of pandemic (H1N1) 2009 may represent 79 total cases, with a 90% probability range of 47 148 10. Using the same multiplier, it is estimated the actual number of Influenza A (H1N1) cases were about 38,710. About 99% of the cases were among people less than 60 years old with a median age of 16 years. This indicates that Influenza A (H1N1) able to infect everybody regardless of his/her age. However, younger age groups were more vulnerable to Influenza A (H1N1) infection. The pandemic A (H1N1) 2009 virus is life-threatening for some patients and mild for most those who were infected 11. In Pahang, there were 5 confirmed deaths due to Influenza A (H1N1) reported. Their age ranges from 5 years to 26 years. This is in contrast to Seasonal Influenza in which complications occur mainly in the extreme age group. As for gender, male and female are both equally affected. Kuantan district reported more than half of the total cases in Pahang. This is due to the fact that nearly 1/3 of Pahang populations are in Kuantan. It also has many public places such as hypermarkets, supermarkets, shopping malls, stadiums and learning institutions which attract peoples and this provide favorable environment for the spread of Influenza A(H1N1) infection. These same factors also correlate with the high numbers of clusters reported in Kuantan. During the pandemic period, surveillance for Influenza-Like Illness (ILI) and Severe Acute Respiratory Infection (sari) were done by daily data collection from 85 government health clinics and 13 health facilities which include all government hospitals and 3 private hospitals respectively. The surveillance indicated that 11,570 cases (2.2%) of outpatients attendances were ILI cases. This figure was almost similar to the national baseline in United States which was 2.3 % 12. Meanwhile, 966 cases (2.0%) of total admissions were SARI cases. ILI and SARI cases reported during the period showed an increasing trend from week 30, peaked at week 33. This was also true to the number of clusters reported where most of the clusters (95%), were reported during the same period. Most people would have probably been exposed or infected during this period which was evidenced by the decreasing number of cases later on. This indicates the swift and brisk transmission of Influenza A (H1N1) within the community. This ILI trend also resembles the trend showed by the confirmed Influenza A (H1N1) cases reported in Pahang. This shows that ILI surveillance is a reliable indicator for detecting Influenza A (H1N1) activity. Public awareness and emphasis on preventive measures such as social distancing, proper hand washing and cough etiquete are important factors in preventing the transmission of Influenza A(H1N1). Realizing this, intensive health promotion activities were carried out all over Pahang. This was done to ensure the public receives a complete, accurate and reliable information. Ministry of Health Malaysia had also set up a dedicated help line and a web page (http://h1n1.moh.gov.my) to ensure members of the public can get up-to-date information on the matter. Pahang State Health Department also initiated its direct helpdesk call number that can be reached for any queries regarding Influenza A (H1N1).
During the pandemic period, various health promotion activities were done by health personnel at district and state level. Private and government practioners were also given updates on the pandemic on regular daily basis via e- mail. Current guidelines, protocols and circulars from the Ministry of Health were disseminated to ensure all activities done in Pahang are in accordance to the national policy. CONCLUSION Influenza A (H1N1) cases showed a decreasing trend and the number of reported cases during the last few weeks were very low. This indicates the slowing down of disease transmission. However, the threat of second wave shouldn t be ignored. This is because widespread influenza activity is being reported throughout North America, with the United States reporting ILI levels elevated above the seasonal baseline for the past month and Mexico reporting a high intensity of respiratory diseases for the past three weeks 7. This Influenza A (H1N1) activity can be monitored through the existing ILI surveillance at the sentinel sites throughout the state which was proven to be useful as a tool for detecting the disease activity in this study. ACKNOWLEDGEMENT The authors would like to express their highest appreciation to Ministry of Health, Malaysia and all the officers and staffs at district health offices, district hospitals and state health department in the state of Pahang, Malaysia for full cooperation in providing information and data for the purpose of this study. It is hoped, this writing could be a resourceful academic reference and could be used further to enhance the health services and management of pandemic influenza in near future. REFERENCES 1. William G. Towards a sane and rational approach to management of Influenza H1N1. Virology Journal 2009; 6: 51. 2. Yang Y, Sugimoto JD, Halloran ME, et al. The transmissibility and control of pandemic influenza A (H1N1) virus. Science 2009; 326(5953): 729 733. 3. Hospital Influenza Workgroup. Management of novel influenza epidemics in Singapore: consensus recommendations from the hospital influenza workgroup (Singapore). Singapore Med. Journal 2009; 50(6): 567-580. 4. Khanna M, Gupta N, Gupta A, Vijayan VK. Influenza A (H1N1): a pandemic alarm. J. Biosci. 2009; 34: 481 489. 5. ECDC Technical Emergency Team (2009). Initial epidemiological findings in the European Union following the declaration of pandemic alert level 5 due to influenza A (H1N1). Available from: http://www.eurosurveillance.org/vie (accessed 22 November 2009). 6. De Rosa FG, Montrucchio C, Di Perri G. Management of H1N1 influenza virus respiratory syndrome. Minerva Anestisiol 2009; 75(11): 654-660. 7. WHO. Pandemic H1N1 2009 - update 69. Geneva: World Health Organization, 2009. Available from: http://www.who.int/csr/don/ (accessed 28 October 2009). 8. WHO. Interim WHO guidance for the surveillance of human infection with swine influenza A (H1N1) virus. Geneva: World Health Organization, 2009. 9. Ministry of Health Malaysia. Mitigation phase: influenza A (H1N1) surveillance strategies, 2009. 10. Reed C. Estimates of the prevalence of pandemic (H1N1). Emerging Infectious Diseases 2009; 15(12): 2004-2007. 11. Hebert PC, MacDonald N. Preparing for pandemic H1N1. Canadian Medical Association Journal 2009; 181: 6-7. 12. CDC. 2009-2010 Influenza Season Week 48, FluView. Atlanta: Centres for Disease Control and Prevention, 2009. Available from: http://www.cdc.gov.my/flu/weekly/fluact ivity.htm (accessed 15 December 2009).