The dominant genotypes of influenza virus and their correspondence to the vaccine strain used in the year 2019-2020

Absract: Respiratory tract infection is the most common cause of illness, especially in developing countries. Influenza remains a major public health problem and an endemic respiratory disease in Iraq, therefore this study was conducted to identify the influenza virus (IV) Types and subtype existed. 2515 nasopharyngeal swaps taken from a hospitalized patients suffering from acute respiratory tract infection a cross sectional study was conducted in Iraq from January 2019 to February 2020. The RT-qPCR was used to detect human IV, and IV genotypes among the study population. The (IV) surveillance showed (33.44%) of tested samples were found positive to the influenza virus including two types A 25.45% , and B11.96%. influenza A subtype which contains H1N1 17.41%, and H3N2 4.05%, and Type B Victoria was represented of positive infection. These findings indicated that subtype H1N1 is the dominant strain in Iraq. The age group under 15 years old is considered the most vulnerable to contracting Influenza type A H1N1 25% and type B viruses (40%) followed by the age group 30-45 years old. On the other hand, the age group 15-30 recorded the highest infection rate 25% out of the total H3N2. The non-significant percentage related to the age of over 75 years to all types and subtypes. Baghdad has the high significances incidence of influenza Type A, and B with the percentage 65.92%, and 52.16% respectively of the total tested cases, followed by Dohuk Governorate by percentage 7.2%, 11.96% respectively. Infections of influenza A subtypes H1N1, and H3N2 were distributed differently among governorates, as the subtype prevailed H1N1 in the governorates Baghdad, Dohuk 5.7%, Diyala 6.84%, Salahaddin 2.05%, The Qar 1.83% respectively, while the subtype H3N2 prevailed in the governorates Anbar 30.4%, Baghdad 17.2%, Erbil 14.70%, Dohuk 13.72%, Basra 9.8/5, Diwaniya 2.94% respectively. The epidemic spread of the virus showed earlier primary peak began from October until the end of February, an increase in infection rates rising in the winter months in both the types Influenza type A with the highest peak in a December, and a decline in the summer of type B and a decrease in the subtype H2N3.