As the temperature has gradually decreased, the influenza season is about to take off. While the quadrivalent vaccine shortage has persisted, parents with children aged below 3 have been questioning the efficacy of the trivalent vaccine as the children getting the influenza vaccine for the first time had previously received one dose of the quadrivalent vaccine and wondering how their children should receive the second dose. On December 11, 2018, the Taiwan Centers for Disease Control (Taiwan CDC) specially invited Dr. Huang Zoning, who is a pediatrician from MacKay Memorial Hospital, to help clarify the parents’ questions.

Dr. Huang pointed out that it takes approximately 2 weeks for a person’s body to develop a full immune response to the vaccine. Since there is no shortage of the government-funded trivalent vaccine (0.25mL) for children and this year’s influenza vaccine strains highly match the circulating strains, he advised parents to vaccinate children aged above 6 months and below 3 years against influenza as soon as possible. In addition, children who will be receiving their first influenza vaccine will need to receive 2 doses of the vaccine, administered at least 4 weeks apart, to ensure the development of a full immune response. If a child has previously received a dose of the quadrivalent or trivalent vaccine, he/she can receive the second dose of the trivalent vaccine without waiting for the quadrivalent vaccine to become available and can still develop a full immune response.

As of December 2018, over 4,760,000 doses of government-funded influenza vaccines have been administered. Approximately, 348,000 doses of the 0.5mL vaccine and 91,000 doses of the 0.25mL vaccine remain. According to the disease surveillance data compiled by Taiwan CDC, from December 2 to 8, the number of people seeking ER and outpatient consultation rates for influenza-like illness was 61,861, which is slightly higher than that the previous week. The overall influenza activity in Taiwan has been on the rise for almost 2 weeks. Additionally, 1 new death associated with influenza infection caused by H3N2 reported last week was confirmed in an over 80-year-old male who resided in central Taiwan and had medical history of chronic condition.

Since October 1, 2018, a cumulative total of 99 cases of influenza complications, including 67 cases caused by H3N2 (67%), have been confirmed. Among the 11 deaths associated with influenza infection, 6 were caused by H3N2 and 5 were caused by H1N1. During the past 4 weeks, H3N2 has been the dominant strain circulating in the community. Recently, influenza activity in temperate countries in the Northern Hemisphere has remained at a low level but has been on the rise. Among the countries, Canada, Korea, the U.S. and Singapore have reported influenza activity above the epidemic threshold. Thus far, the dominant strain in most countries has been H1N1. However, Singapore and Europe have all reported H1N1 and H3N2 as the dominant strains circulating in their communities.

Taiwan CDC once again reminds the public that in addition to receiving the annual seasonal influenza vaccine, practicing good personal hygiene such as paying additional attention to respiratory hygiene and cough etiquette, and avoiding visits to crowded and poorly ventilated public places to prevent influenza.  Moreover, once influenza-like symptoms develop, infected individuals should put on a surgical mask, seek immediate medical attention, rest at home, and only resume school or work after full recovery to prevent the further spread of the virus that could lead to outbreaks. Individuals with influenza-like illness fitting the criteria for government-funded influenza antivirals will be prescribed the drug by the physician without the use of a rapid influenza diagnostic test. For more information, please visit the Taiwan CDC website at http://www.cdc.gov.tw or call the toll-free Communicable Disease Reporting and Consultation Hotline, 1922 (or 0800-001922).