Influenza pandemic: preparedness planning in Germany

Case Study – Germany

Public health structures in Germany reflect the federal system: health care in general lies within the responsibility of the 16 constituent states and the federal government only acts if a state asks for assistance. There were no bioterror-related intentional releases of biological agents in Germany in recent years. The potentially devastating effects of such an incident require sound public health preparedness planning. The Basic Constitutional Law (Grundgesetz) does not allow the deployment of armed forces within Germany with some rare exceptions. However, there is a well-established civil-military cooperation. The Federal Armed Forces (Bundeswehr) are deployed in humanitarian and multinational UN or NATO crisis containment missions abroad, requiring adequate protection from pathogens and diseases endemic or enzootic to those regions. Both, the military and the civil public health system are complex structures that contain administrative, care giving, medical investigation, and research capabilities in order to cope with natural, accidental or intentional biological incidents.

Simple criteria for finding (nearly) optimal vaccination strategies

Strategies for best controlling the spread of the diseases with limited vaccine available are explored. I use influenza as a representative disease in point. The model describes the dynamics of influenza spread among multiple groups that have different risks and activity levels. I define a core group consisting of individuals with occupations that brings them in contact with many other people in a day. These occupations may include service industries, teachers, health care, and government workers, to name a few. High-risk individuals are those as typically designated for: children under 5 and adults over 50, people with weakened immune systems as well as emergency and health care personnel. Under certain conditions, shifting vaccination resources away from the high-risk group to the high-activity group will result in improved herd immunity in both the high-risk group and the population as whole. This results in more high-risk people protected even though less of them are being vaccinated, with the obvious implications that current vaccination policies may be far less then optimal. I show that the criteria for the optimal strategy can be derived from simple expressions gleaned from the expression for the basic reproductive number.

FluSurge--a tool to estimate demand for hospital services during the next pandemic influenza

PURPOSE

To assess the impact of pandemic influenza on hospital services.

METHODS

Based on census data and estimates of hospital resources (non-ICU [intensive care unit] beds, ICU beds, and mechanical ventilators) in a given area, FluSurge software estimates the number of hospital admissions and deaths due to pandemic influenza under variable duration and virulence scenarios and compares hospital resources needed during a pandemic with existing hospital resources.

RESULTS

Sample results from Metropolitan Atlanta illustrate how the next influenza pandemic may overwhelm existing hospital resources, given that hospitals increasingly operate at nearly full capacity.

CONCLUSIONS

Hospitals need to consider and plan for a surge in demand for hospital services during the next influenza pandemic.

Influenza pandemic preparedness in France: modelling the impact of interventions

BACKGROUND

Influenza pandemics result in excess mortality and social disruption. To assist health authorities update the French pandemic plan, the authors estimated the number of health events (cases, hospitalisations, and deaths) in a pandemic and compared interventions in terms of impact and efficiency.

METHOD

A Monte Carlo simulation model, incorporating probability distributions of key variables, provided estimates of health events (HE) by age and risk group. Input variables were set after literature and expert consultation. The impact of targeted influenza vaccination and antiviral prophylaxis/treatment (oseltamivir) in high risk groups (elderly, chronic diseases), priority (essential professionals), and total populations was compared. Outcome measures were HE avoided, number of doses needed, and direct cost per HE avoided.

RESULTS

Without intervention, an influenza pandemic could result in 14.9 million cases, 0.12 million deaths, and 0.6 million hospitalisations in France. Twenty four per cent of deaths and 40% of hospitalisations would be among high risk groups. With a 25% attack rate, 2000-86,000 deaths could be avoided, depending on population targeted and intervention. If available initially, vaccination of the total population is preferred. If not, for priority populations, seasonal prophylaxis seems the best strategy. For high risk groups, antiviral treatment, although less effective, seems more feasible and cost effective than prophylaxis (respectively 29% deaths avoided; 1800 doses/death avoided and 56% deaths avoided; 18,500 doses/death avoided) and should be chosen, especially if limited drug availability.

CONCLUSION

The results suggest a strong role for antivirals in an influenza pandemic. While this model can compare the impact of different intervention strategies, there remains uncertainty surrounding key variables.

Potential Impact of Antiviral Drug Use during Influenza Pandemic

The recent spread of highly pathogenic strains of avian influenza has highlighted the threat posed by pandemic influenza. In the early phases of a pandemic, the only treatment available would be neuraminidase inhibitors, which many countries are considering stockpiling for pandemic use. We estimate the effect on hospitalization rates of using different antiviral stockpile sizes to treat infection. We estimate that stockpiles that cover 20%-25% of the population would be sufficient to treat most of the clinical cases and could lead to 50% to 77% reductions in hospitalizations. Substantial reductions in hospitalization could be achieved with smaller antiviral stockpiles if drugs are reserved for persons at high risk.

Influenza a common viral infection among Hajj pilgrims: time for routine surveillance and vaccination

BACKGROUND

The annual Hajj pilgrimage to Mecca, Saudi Arabia brings over two million people to a small confined area. Respiratory tract infection is the most common disease transmitted during this period. For most of the etiologic agents of upper respiratory tract infections, no vaccine or prophylaxis is available, except for influenza. Yearly influenza vaccination of high-risk groups is recommended, but no special recommendations are available for those performing the Hajj or other similar large congregational activities. Viral surveillance studies are being carried out through more than 100 centers around the world to identify newly emerging viruses. Saudi Arabia is not one of those centers and no routine surveillance takes place.

METHODS

Five hundred Hajj pilgrims presenting with upper respiratory tract symptoms from different parts of the world were screened by way of a throat swab for viral culture, including influenza A and B, parainfluenza, respiratory syncytial virus (RSV), adenovirus, herpes simplex virus (HSV), and enteroviruses. Information was collected on age, sex, nationality, smoking habits and upper respiratory tract symptoms. Vaccination status for influenza and meningococcus was obtained by self-declaration, since most pilgrims did not have their vaccination cards with them. Only those with symptoms including at least fever, reported by the patient to be >38.3 degrees C, and/or sore throat were included. Pilgrims with any other symptoms, especially myalgia and fatigue alone, were excluded, since many of the physical chores during the pilgrimage may contribute to such symptoms.

RESULTS

Fifty-four patients (10.8%) had positive viral throat cultures. Of these, 27 (50%) were influenza B, 13 (24.1%) were HSV, 7 (12.9%) were RSV, 4 (7.4%) were parainfluenza, and 3 (5.6%) were influenza A. No enteroviruses or adenoviruses were detected, and no multiple infections were detected. Only 22 (4.7%) pilgrims received the influenza vaccine. When the results are applied to the total number of pilgrims in 2003, an estimate of 24,000 cases of influenza is obtained.

CONCLUSION

The findings from this study suggest a high incidence of influenza as a cause of upper respiratory tract infection among pilgrims, estimated to be 24,000 cases per Hajj season, excluding those becoming ill from contact with Hajj pilgrims returning home. They also indicate a very low vaccination rate for the influenza vaccine; as well as poor knowledge of its existence. Continued surveillance during the Hajj pilgrimage is necessary. The influenza vaccine should be a priority for those attending the Hajj pilgrimage, and should also be considered for antiviral prophylaxis.