Summary

Knowledge of issues related to pandemic influenza is important to primary care physicians in order to address patients' questions and prepare for its occurrence. Compared with SARS, the next influenza pandemic will claim many times more human lives and economic losses. The Hong Kong Government's three-tier Pandemic Influenza Preparedness Framework is a useful reference for primary care physicians. Primary care physicians have several key roles in pandemic influenza. They are essential in picking up early cases of pandemic influenza and monitoring the progress of the epidemic in the community. They will provide the bulk of outpatient medical consultations and they are in the unique position of prescribing antivirals. Enterprises also depend on primary care physicians for advice in business continuity plans and infection control. Primary care physicians can also assist in carrying out public health functions by enrolling in a volunteer doctors' scheme coordinated by the Government and professional medical organizations. In summary, primary care physicians represent a very special and irreplaceable pool of expert resource. Many peoples' lives in Hong Kong will depend on their readiness and response in an influenza pandemic.

摘要

基層醫生要對流感大流行有足夠的理解和知識才能解答病人的問題，和為它的來臨作出準備。與嚴重急性呼吸道綜合症相比，流感大流行將對人類生命和經濟造成更大的損害。香港政府的三級制流感大流行應變計劃，可供基層醫生作為有用的參考。到時基層醫生將會擔當多種關鍵性的角色。首先，基層醫生能辨認出疫症早期的病例、以及監察著疫症在社區爆發的進度。他們會為眾多的病人提供門診服務，負上為病人處方抗病毒藥物的獨特工作。企業亦信賴基層醫生為他們提供控制感染建議以便制定方案使商務繼續營運。基層醫生亦能藉參與由政府和醫學界團體協辦的志願計劃，為大眾提供公共衛生服務。總而言之，基層醫生代表著一股獨特而無可代替的專業資源。當流感大流行爆發時，很多香港市民的性命將倚賴基層醫生在這方面的充份準備及迅速反應。

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Introduction

For the primary care doctor/family physician (FP), pandemic influenza may seem a remote matter in his/her daily practice. Pandemic influenza itself is a not an easy subject to grapple with because of its rapidly changing knowledge and pattern. Still, there are good reasons for the FP to be concerned. Firstly, attending patients would often ask questions since this issue is often featured prominently in the local media. More importantly, the unprepared doctor and his patients will suffer dearly should pandemic influenza arrive with little warning.

How bad would it be?

In 2006, avian influenza H5N1 expanded notably across geographical boundaries, stretching to the Middle East, Africa, and Central Europe. Over 44 human cases have been reported in Southeast Asia (e.g., Indonesia, China, Thailand, Vietnam), with Indonesia bearing the greatest brunt.¹ Most humans became infected through contact with infected poultry. At this point-of-time, human-to-human transmission has been documented only in some family clusters but not in the wider community.^2,3 Even with current technology it is impossible to tell exactly when the virus would acquire the ability to transmit efficiently between humans and set off a pandemic. Another concern is that a possible pandemic influenza virus could be other than the H5N1 strain (e.g., an H2 virus).

According to the World Health Organization, an H5N1 pandemic could affect 1-2 billion people worldwide, killing several million people and causing US$2 trillion in economic losses.^4,5 The estimated number of hospitalizations and outpatient visits could reach 1.5-5.2 millions and 134-233 millions respectively.⁵ If the next pandemic were to have the same attack rate (15%) as the previous "Hong Kong flu" pandemic of 1968, approximately one million people in Hong Kong could fall ill within 6-8 weeks in the primary wave.⁶ The strain on the healthcare system and society as a whole would be beyond imagination.

What roles can FPs play?

FPs have major role to play in Hong Kong's contingency plan for avian and pandemic influenza, which is being rated favourably among developed countries.⁷ The contingency plan has 3 "Response Levels". In simple terms, at the "Alert" Response Level, poultry outbreaks or human cases of avian influenza are occurring in countries outside Hong Kong. At the "Serious" Response Level, poultry outbreaks or human cases of avian influenza appear in Hong Kong without efficient human-to-human transmission. At the "Emergency" Response Level, there is evidence of efficient human-to-human transmission of avian influenza regardless of location; or a pandemic is declared by the World Health Organization (WHO). Each Response Level prescribes a set of public health measures involving surveillance, case investigation and control, quarantine and isolation, border health, antivirals and vaccines, infection control, social distancing, risk communication and so on.⁸

FPs can help detect cases and monitor progression of epidemic

Doctors are required by law to notify the Department of Health (DH) of suspected cases of avian influenza H5, H7 and H9 (Central Notification Office tel: 2477 2772). Reporting criteria are shown in the website of DH's Centre for Health Protection (CHP) at https://ceno.chp.gov.hk/index2.jsp. Once a doctor reports a suspected case, CHP staff will contact the doctor and arrange for laboratory confirmation as well as necessary control measures. Free confirmatory laboratory service is provided by the CHP. Laboratory test results for H5 using Real Time Polymerase Chain Reaction (RT-PCR) normally takes about 3 hours to complete.

FPs enlisted in the CHP's sentinel surveillance programme play a key role in monitoring the progression of the epidemic in the community (this was in fact done in the 1968 Hong Kong flu). The data they provide is used to analyze which direction the epidemic is taking. This information is crucial to healthcare providers in planning their services and to the general community as to what to expect.

FPs can provide medical services during pandemic influenza

The vast majority of patients will be treated in the outpatient setting during a pandemic influenza. Many of them will come under the hands of their FPs. During this time, laboratory confirmation on individual patients will no longer be necessary or practical. Patients with flu-like illnesses can be managed presumptively as pandemic influenza.

FPs are advised to stockpile antivirals for treating patients and their own prophylaxis during pandemic influenza. The CHP's Scientific Committee on Emerging and Zoonotic Diseases has published updated guidelines (August 2006) on the use of antivirals. Three indications for antiviral use are defined, namely for (i) patient treatment, (ii) post-exposure prophylaxis of contacts, and (iii) pre-exposure prophylaxis for healthcare workers with at least moderate risk of exposure, essential services providers, and workers involved in culling operations. Box 1 shows the recommendations for antiviral treatment for pandemic influenza patients.

Box 1: Antiviral treatment for pandemic influenza

Oseltamivir should be administered as soon as possible, preferably within 48 hours after the onset of symptoms, to achieve maximum efficacy. Adults & adolescents 13 years of age or above 75 mg BD x 5 days (standard regimen) Children between 1 and 12 years of age <15 kg: >15 - 23 kg: >23 - 40kg: > 40kg: 30 mg BD x 5 days 45 mg BD x 5 days 60 mg BD x 5 days 75 mg BD x 5 days Infants Safety and efficacy as a therapeutic agent for infants (<12 months of age) have not been established. However, it may be considered for treatment (off label use) in this age group when the benefits are expected to outweigh the risks. Dosages should be adjusted according to body weight. (Recommendation: 2 mg/kg BD) Zanamivir might be considered as an alternative treatment agent for patients who are able to use the diskhaler device but the recommendation is classified as weak by the WHO. Amantadine or rimantadine alone should not be used as a first-line treatment for patients with confirmed or strongly suspected H5N1 infection except when neuraminidase inhibitors are not available for treatment and local data show that the H5N1 virus is known or likely to be susceptible.

FPs enrolled in the CHP's volunteer doctors scheme can work in any one of the 18 designated public clinics where antivirals are available to patients. Moreover, private doctors may receive referrals of semi-emergency or elective cases from the public sector (e.g., patients with chronic diseases), when the latter is required to focus resources on treating pandemic influenza patients.

FPs can educate patients on personal hygiene to reduce transmission risk

As most patients during pandemic influenza will be managed at home, FPs are in the best position to advise them on personal hygiene to reduce transmission risk to other family members. The patient should wear a mask and avoid mixing with family members or sharing utensils of daily living with them. He should maintain good hand hygiene through handwashing with soap/water or alcohol-based hand rinse. Objects or surfaces soiled with the patient's secretions should be properly disposed of (e.g., in a plastic bag) or disinfected (e.g., 1:49 hypochlorite/household bleach).

The FP must also have sufficient quantities of personal protective equipment in his clinic and adhere to appropriate infection control measures. Guidelines for infection control at the primary care setting are available at the CHP's website http://www.chp.gov.hk/files/pdf/grp_IC_practice_during_flu_pandemic2005011102.pdf.

FPs can help enterprises get prepared for pandemic influenza

Some FPs provide medical services to private enterprises. These enterprises may seek their advice on pandemic influenza preparations for sake of business continuity. The FP's advice may cover issues related to prevention of infectious diseases, infection control practice, disinfection in the workplace, stockpiling of personal protective equipment, use of antivirals, sick leave policy and others.

For an enterprise that wishes to establish an antiviral stockpile for business continuity, the FP can discuss with the enterprise the extent of coverage desired for its employees, which varies with the policy of individual enterprise. From a business continuity perspective, priority is given to employees required to sustain core operations of the enterprise or are at risk of infections at work, whose absence from work would lead to suspension of business. Taking into consideration the treatment regime and the number of employees to be covered, the FP can estimate the amount of antivirals required for treatment of infected staff. Depending on the amount of antivirals to be stockpiled, a suitable place for storage needs to be identified. Also, an advance delivery schedule has to be worked out with the drug supplier. Doctors should convey clearly to enterprises the conditions under which the stockpile should be mobilized to avoid misunderstanding. Last but not least, doctors should only prescribe antivirals to enterprise employees after a proper medical consultation. Guidelines are accessible at the CHP website: http://www.chp.gov.hk/view_contentf7e0.html?lang=en&info_id=590.

FPs can assist in carrying out public health functions in pandemic influenza

The CHP has set up a volunteer doctors scheme in collaboration with the Hospital Authority, Hong Kong Medical Association, Hong Kong Doctors Union, Practising Estate Doctors' Association Ltd, the Hong Kong Chinese Medical Association, and Association of Licentiates of Medical Council of Hong Kong. Doctors enrolled in the scheme are entitled to participate in carrying out certain public health functions (e.g., public education programmes, vaccination, supervising hotline services) as well as clinical duties in public clinics and hospitals. At the time of writing, around 200 doctors have already joined this scheme. Interested doctors can contact any one of the above medical organisations or CHP for more information.

Resources for FPs

FPs can access the CHP website (www.chp.gov.hk) for frequent updates on avian and pandemic influenza. A dedicated column is tailored for medical professionals, containing the latest medical information and guidelines. FPs also receive regular emails and letters from the CHP concerning significant developments in avian or pandemic influenza. The CHP has organized training on infection control for FPs and special training for doctors enrolled in the volunteer doctors scheme.

Conclusion

FPs play a very special and indispensable role in pandemic response. As gatekeepers for the health of the community, they represent a massive and irreplaceable pool of professional expertise and service capacity. The readiness of the FP may make or break a successful pandemic response.

Key messages

1. FPs can help detect cases and monitor progression of epidemics.
2. FPs can provide medical services during pandemic influenza.
3. FPs can educate patients on personal hygiene to reduce transmission risk.
4. FPs can help enterprises get prepared for pandemic influenza.
5. FPs' readiness can make or break a successful pandemic response.

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References