| Abstrakt: |
A mathematical model has been established to predict the spread rate of Influenza A H1N1 outbreak in the kingdom of Bahrain to allow the ministry of health to response effectively to such a pandemic disease. Based on this model, which can be used on any other country, the expected number of infected cases can be determined. This has been done taken in consideration four factors in the model: spread of the virus through the schools, through affected people visiting Bahrain from overseas countries, through social behavior, and finally through spread from other factors like weather, building, population density…etc. This model calculates the expected cases and deaths in the kingdom of Bahrain for different age groups by the end of 2009, end of June 2010 and end of 2010 taking in consideration the condition of vaccinating the citizens and residents of Bahrain in different proportions ( by 10%, 50%, and 75% of the population) or without vaccination at all. In addition, the expected spread of the disease was calculated in Bahrain based on the effect of vaccinating Bahrain's pilgrimages or without vaccinating. Three scenarios were developed and they differ from each other by the weight given to each factor of the four factors mentioned above. The results indicate that the second scenario (assuming weight of 25% for the spread of the A H1N1 virus by school, 15% for affected people arriving from abroad, 40% for social behavior, and 20% for other factors like weather, building, population density…etc) gives the largest number of expected cases and deaths. It indicates that the total number of A H1N1 may reach to 12,669 infected cases without taking firm precautions and 824 with the recommended firm precautions ( but without taking the vaccine) by the end of 2009, while it may reach to 223,760 and 22,148 infected case by the end of 2010, respectively. These calculations were based on the results of confirmed cases done by ministry of health, but if the clinically suspected cases were considered also, the model indicate that the expected cases of H1N1 will reach to 17,708 cases without firm precautions and 1,082 with firm precautions by the end of 2009, while it will be 865,202 and 38,232 cases by the end of 2010, respectively. As for the deaths (without taking the vaccine), it will be 8 with firm precautions by the end of 2009 and 37 deaths by end of 2010. The model indicates that the most affected age group by A H1N1 virus is those of age between 25-34 years with 107 infected case if firm precautions taken and 1,646 without firm precautions until the end of 2009 in the first scenario, while it may reach to 214 cases and 2,312 cases in the second scenario and 184 cases and 2,061 cases in the third scenario, respectively. Based on the model, if 10 % of the population of Bahrain received the vaccine - taking in consideration the other precautions (by beginning of November 2009)- the expected number of cases will be 704 by the end of 2009 (in comparison to 824 cases when firm precaution taken and considering confirmed cases only). It will rise to 20,314 infected case by the end of 2010 (in comparison to 21,985 cases when firm precaution taken and considering confirmed cases only). On the other hand, if 50% of Bahrain's population received the vaccine, the number of cases will decrease to 147 cases by the end of 2009 and to 4,265 by the end of 2010, while it will be reduced to 14 cases by the end of 2009 and to 426 by end of 2010 if 75% of the population received the vaccine. Finally, the results indicate that if the vaccination is not mandatory for pilgrimage - according to the special model for spread of A H1N1 virus in Bahrain by pilgrimages this year (7,000 pilgrimages) - than the expected cases among pilgrimages will be around 1470 cases. This will lead to the infection of 4,356 person with H1N1 in the kingdom of Bahrain (when the pilgrimages return home and mix with relatives and friends) by the end of 2009, while the infection will decrease to 230 cases only and lead to 1,800 cases among the contacts in case the vaccination become mandatory for pilgrimages. The previous calculations were based on the assumption that the least vaccine efficacy is 85%. This means that making the vaccine mandatory for pilgrimages will protect 2556 persons from getting the disease in Bahrain. [ABSTRACT FROM AUTHOR] |
