{"id":39207,"date":"2026-03-17T19:55:09","date_gmt":"2026-03-17T11:55:09","guid":{"rendered":"https:\/\/www.hkioc.com.hk\/?page_id=39207"},"modified":"2026-03-27T17:28:57","modified_gmt":"2026-03-27T09:28:57","slug":"influenza-vaccine","status":"publish","type":"page","link":"https:\/\/www.hkioc.com.hk\/en\/influenza-vaccine\/","title":{"rendered":"Influenza Vaccine"},"content":{"rendered":"

[vc_row][vc_column][vc_empty_space][vc_custom_heading text=”Why do cancer patients especially need influenza vaccination?” font_container=”tag:h2|text_align:center|color:%235e3327″ use_theme_fonts=”yes”][vc_text_separator title=”” color=”custom” border_width=”2″ el_width=”10″ accent_color=”#ffa800″][vc_empty_space][vc_column_text]Influenza, also known as seasonal flu, is an acute respiratory infection caused by influenza viruses. Most healthy individuals recover within a few weeks, but for patients who are undergoing cancer treatment or who have suppressed immune function, influenza may quickly lead to serious complications, hospitalization, or even become life-threatening.<\/p>\n

Influenza spreads mainly through droplets and contact. Routine preventive measures include hand hygiene and mask-wearing when appropriate. Vaccination is one of the most effective ways to prevent influenza and its serious consequences. Cancer patients, as well as their family members and caregivers, are advised to receive influenza vaccination every year to establish more comprehensive protection.[\/vc_column_text][\/vc_column][vc_column][vc_empty_space][vc_custom_heading text=”Local circulation of influenza viruses” font_container=”tag:h2|text_align:center|color:%235e3327″ use_theme_fonts=”yes”][vc_text_separator title=”” color=”custom” border_width=”2″ el_width=”10″ accent_color=”#ffa800″][vc_empty_space][vc_column_text]In Hong Kong, seasonal influenza peaks usually occur from January to March or April, and again from July to August each year. The seasonal influenza viruses known to infect humans are mainly classified into three types: influenza A, influenza B, and influenza C.<\/p>\n

Because influenza viruses mutate frequently and new strains regularly emerge, the World Health Organization updates the recommended vaccine composition every year based on global surveillance data. For patients receiving cancer treatment, vaccination with a formulation that matches currently circulating strains is an important step in achieving effective protection.<\/p>\n

[\/vc_column_text][vc_empty_space][vc_single_image image=”38969″ img_size=”large” alignment=”center”][vc_empty_space][vc_empty_space][vc_column_text]Figure: Percentage of respiratory specimens tested positive for influenza virus subtypes, January 2023 to August 2024. Extracted from Communicable Diseases Watch (accessed January 2026).<\/p>\n

Influenza viruses are highly mutable and highly contagious. Symptoms are generally more severe than those of the common cold, and serious complications are more likely.[\/vc_column_text][vc_empty_space][vc_column_text]<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n
Item<\/strong><\/td>\nCommon Cold<\/strong><\/td>\nInfluenza<\/strong><\/td>\n<\/tr>\n
Cause<\/td>\nVarious viruses (e.g. rhinoviruses, adenoviruses)<\/td>\nInfluenza viruses<\/td>\n<\/tr>\n
Scope of illness<\/td>\nMainly localized upper respiratory symptoms<\/td>\nSystemic illness<\/td>\n<\/tr>\n
Onset<\/td>\nGradual (sometimes relatively sudden)<\/td>\nSudden<\/td>\n<\/tr>\n
Main symptoms<\/td>\nUsually milder: sore throat, nasal congestion, runny nose, sneezing, mild cough<\/td>\nUsually more severe: high fever, marked muscle aches, headache, extreme fatigue, dry cough, sore throat<\/td>\n<\/tr>\n
Fever<\/td>\nUncommon, or only slight fever<\/td>\nHigh fever is common (above 38.5\u00b0C), often lasting 3\u20134 days<\/td>\n<\/tr>\n
Course<\/td>\nAbout 2\u20135 days (most improve within 7 days)<\/td>\nAbout 1\u20132 weeks (fatigue may last longer)<\/td>\n<\/tr>\n
Transmission<\/td>\nDroplet spread and contact spread<\/td>\nDroplet spread and contact spread<\/td>\n<\/tr>\n
Contagiousness<\/td>\nVariable<\/td>\nHighly contagious<\/td>\n<\/tr>\n
Complications<\/td>\nUncommon (occasionally otitis media, sinusitis, or mild pneumonia)<\/td>\nMore common and potentially serious: pneumonia, encephalitis, myocarditis, secondary bacterial infection, etc.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

[\/vc_column_text][\/vc_column][vc_column][vc_empty_space][vc_custom_heading text=”Groups at high risk from influenza” font_container=”tag:h2|text_align:center|color:%235e3327″ use_theme_fonts=”yes”][vc_text_separator title=”” color=”custom” border_width=”2″ el_width=”10″ accent_color=”#ffa800″][vc_empty_space][vc_column_text]Influenza can affect people of all ages. Once high-risk individuals are infected, they are more likely to develop severe complications such as pneumonia, encephalitis, myocarditis, secondary infections, or neurological manifestations; in severe cases, influenza can be fatal. Extra vigilance is therefore required.<\/p>\n

1.Infants and children younger than 5 years<\/strong><\/p>\n

2.Adults aged 65 years or above<\/strong><\/p>\n

3.People with chronic illnesses, including asthma, heart disease, lung disease, diabetes, and chronic kidney disease<\/strong><\/p>\n

4.People with weakened immunity, including patients with cancer<\/strong><\/p>\n

5.Pregnant women<\/strong><\/p>\n

[\/vc_column_text][\/vc_column][vc_column][vc_empty_space][vc_custom_heading text=”Timing of influenza vaccination and precautions” font_container=”tag:h2|text_align:center|color:%235e3327″ use_theme_fonts=”yes”][vc_text_separator title=”” color=”custom” border_width=”2″ el_width=”10″ accent_color=”#ffa800″][vc_empty_space][vc_column_text]Except for people with known contraindications, all cancer patients are generally advised to receive influenza vaccination before the winter influenza season, so the body has enough time to build immune protection and strengthen its defense against the virus.[\/vc_column_text][vc_column_text]<\/p>\n\n\n\n\n\n\n\n\n\n\n\n
<\/td>\nInactivated Vaccine<\/strong><\/td>\nLive Attenuated Vaccine<\/strong><\/td>\nRecombinant Vaccine<\/strong><\/td>\n<\/tr>\n
Composition<\/td>\nKilled virus<\/td>\nWeakened live virus<\/td>\nVirus surface antigen produced using recombinant technology<\/td>\n<\/tr>\n
Coverage<\/td>\nTrivalent or quadrivalent<\/td>\nTrivalent<\/td>\nTrivalent<\/td>\n<\/tr>\n
Route<\/td>\nIntramuscular or subcutaneous injection<\/td>\nIntranasal spray<\/td>\nIntramuscular injection<\/td>\n<\/tr>\n
Age group<\/td>\n6 months of age or above (including people with chronic disease)<\/td>\n2\u201349 years<\/td>\n18 years or above (including pregnant women)<\/td>\n<\/tr>\n
Contraindications<\/td>\nSevere allergic reaction to a previous dose; severe allergy to any vaccine component such as gelatin or antibiotics. Mild egg allergy alone (e.g. urticaria only) is usually not a contraindication, but vaccination should be given in a setting equipped to manage allergic reactions.<\/td>\nPregnancy; immunocompromised individuals (e.g. cancer patients receiving chemotherapy, transplant recipients, people with HIV\/AIDS); severe asthma or asthma requiring emergency care\/hospitalization in the previous 12 months; children or adolescents taking aspirin or salicylate-containing medicines; severe allergy to vaccine components including gelatin or antibiotics.<\/td>\nSevere allergic reaction to a previous dose or to any vaccine component. People with bleeding disorders or those taking anticoagulants can still be vaccinated, but should inform healthcare staff so injection-related precautions can be arranged, such as using a fine needle and applying pressure longer after injection.<\/td>\n<\/tr>\n
Common side effects<\/td>\nInjection-site pain and redness, muscle aches, fatigue, fever, chills<\/td>\nMild nasal congestion or runny nose, low-grade fever, sore throat<\/td>\nInjection-site pain and redness, muscle aches, fatigue, fever, chills<\/td>\n<\/tr>\n
Protective effect<\/td>\nEffective in preventing influenza and its complications; safety has been widely confirmed<\/td>\nEffective in preventing influenza and its complications; safety has been widely confirmed<\/td>\nEffective in preventing influenza and its complications; safety has been widely confirmed<\/td>\n<\/tr>\n
Recommendation<\/td>\nRecommended for use in Hong Kong by the Scientific Committee on Vaccine Preventable Diseases<\/td>\nRecommended only for appropriate eligible recipients<\/td>\nMay be considered where suitable and available<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

[\/vc_column_text][\/vc_column][vc_column][vc_empty_space][vc_custom_heading text=”Frequently Asked Questions (FAQ)” font_container=”tag:h2|text_align:center|color:%235e3327″ use_theme_fonts=”yes”][vc_text_separator title=”” color=”custom” border_width=”2″ el_width=”10″ accent_color=”#ffa800″][vc_empty_space][vc_accordion][vc_accordion_tab title=”1. Why do cancer patients need influenza vaccination?” tab_id=”1773745821-1-40″][vc_column_text] Reduce the risk of severe illness: Patients with cancer often have weakened immunity during treatment, so influenza infection is more likely to lead to pneumonia, sepsis, and other serious complications. Vaccination significantly reduces the risk of severe illness and hospitalization. Maintain treatment continuity: Influenza infection may force delays or interruptions in chemotherapy, radiotherapy, or immunotherapy. Vaccination helps keep cancer treatment on schedule. [\/vc_column_text][\/vc_accordion_tab][vc_accordion_tab title=”2. Which type of influenza vaccine is suitable for cancer patients? Is it safe?” tab_id=”1773745821-2-8″][vc_column_text]For most immunocompromised individuals, non-live vaccines are preferred. Inactivated influenza vaccine or recombinant influenza vaccine is generally recommended because both are non-live and have a better safety profile in this setting. The actual vaccine product and vaccination plan should still be confirmed with the treating doctor.[\/vc_column_text][\/vc_accordion_tab][vc_accordion_tab title=”3. What reactions are common after vaccination, and what should I do?” tab_id=”1773745821-2-9″][vc_column_text]Most reactions are mild and temporary, and usually resolve within a few days. Common reactions include pain at the injection site, transient fatigue, and low-grade fever. Severe allergic reactions are very rare, but if breathing difficulty, facial swelling, or a severe rash occurs, seek medical attention immediately.[\/vc_column_text][\/vc_accordion_tab][vc_accordion_tab title=”4. I am receiving chemotherapy. Can I still receive influenza vaccination?” tab_id=”1773745821-2-10″][vc_column_text]In general, yes. Vaccination is often arranged during a recovery period between chemotherapy cycles or completed before chemotherapy starts. Please discuss this with your treating doctor so the timing can be aligned with your treatment schedule.[\/vc_column_text][\/vc_accordion_tab][vc_accordion_tab title=”5. Will influenza vaccination worsen cancer treatment side effects or interact with medication?” tab_id=”1773745821-2-11″][vc_column_text]Current clinical evidence has not shown that influenza vaccination significantly increases the toxicity or adverse effects of chemotherapy or similar treatment. However, each patient is different, so the final decision should be based on professional assessment of your health status and medication regimen.[\/vc_column_text][\/vc_accordion_tab][\/vc_accordion][\/vc_column][vc_column][vc_empty_space][vc_custom_heading text=”Our vaccination service and arrangements” font_container=”tag:h2|text_align:center|color:%235e3327″ use_theme_fonts=”yes”][vc_text_separator title=”” color=”custom” border_width=”2″ el_width=”10″ accent_color=”#ffa800″][vc_empty_space][vc_column_text]Our clinic provides seasonal influenza vaccination in line with recommendations from Hong Kong\u2019s Centre for Health Protection. To ensure vaccination is safe and effective, please inform us of your current cancer treatment status during consultation. Our healthcare team will assess your condition and arrange the most appropriate timing for vaccination. If you have any questions or would like further information, please feel free to consult our healthcare staff.[\/vc_column_text][vc_empty_space][vc_custom_heading text=”References” font_container=”tag:h2|text_align:center|color:%235e3327″ use_theme_fonts=”yes”][vc_text_separator title=”” color=”custom” border_width=”2″ el_width=”10″ accent_color=”#ffa800″][vc_empty_space][vc_column_text]1.Centre for Health Protection. Seasonal Influenza. Accessed January 2026.<\/p>\n

2.HKSAR Centre for Health Protection, Scientific Committee on Vaccine Preventable Diseases. Recommendations on Seasonal Influenza Vaccination for the 2020\u201321 Season in Hong Kong (as of 29 May 2020). Accessed January 2026.<\/p>\n

3.Centers for Disease Control and Prevention. Signs and Symptoms of Flu | Influenza (Flu).<\/p>\n

4.Drug Office. Seasonal Influenza Vaccination. Accessed January 2026.[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text]<\/p>\n

[\/vc_column_text][\/vc_column][\/vc_row]<\/p>\n","protected":false},"excerpt":{"rendered":"

[vc_row][vc_column][vc_empty_space][vc_custom_heading text=”Why do cancer patients especially need influenza vaccination?” font_container=”tag:h2|text_align:center|color:%235e3327″ use_theme_fonts=”yes”][vc_text_separator title=”” color=”custom” border_width=”2″ el_width=”10″ accent_color=”#ffa800″][vc_empty_space][vc_column_text]Influenza, also known as seasonal flu, is an acute respiratory infection caused by influenza viruses. Most healthy individuals recover within a few weeks, but for patients who are undergoing cancer treatment or who have suppressed immune function, influenza may quickly<\/p>\n","protected":false},"author":14,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"yst_prominent_words":[],"class_list":["post-39207","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/pages\/39207","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/users\/14"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/comments?post=39207"}],"version-history":[{"count":12,"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/pages\/39207\/revisions"}],"predecessor-version":[{"id":39368,"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/pages\/39207\/revisions\/39368"}],"wp:attachment":[{"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/media?parent=39207"}],"wp:term":[{"taxonomy":"yst_prominent_words","embeddable":true,"href":"https:\/\/www.hkioc.com.hk\/en\/wp-json\/wp\/v2\/yst_prominent_words?post=39207"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}