Vaccine Info

Influenza Vaccines

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Last reviewed
December 6, 2021

Flu Shots for 2021-2022 - What's New

Influenza vaccines, known as flu shots, protect people against viruses that research indicates will be most common during the upcoming flu season. 

Most importantly, influenza vaccines do not cause seasonal flu since they are made with either killed or weakened viruses. Influenza vaccines are manufactured differently, and different preparations have different indications as licensed by the U.S. FDA.

The types of influenza vaccine include inactivated influenza vaccines (IIV) and live attenuated influenza vaccines (LAIV). In addition, two new influenza vaccines have been licensed for use in people aged 65 and older; a quadrivalent high-dose influenza vaccine and a quadrivalent adjuvanted influenza vaccine.

On June 24, 2021, the CDC's vaccine committee reviewed Influenza Vaccines Expected to be Available by Age Indication, United States, 2021–22 Influenza Season. The ACIP affirmed the updated MMWR Recommendations and Reports.

The European Medicines Agency announced its flu shot recommendations for the Fall of 2021. Additionally, the WHO recommended on September 24, 2021, the composition of influenza virus vaccines for use in the 2022 southern hemisphere influenza season. In addition, the WHO reports current influenza trends at this link.

The CDC issued Health Alert Advisory (CDCHAN-00458) on November 24, 2021, about increased influenza A(H3N2) activity in the U.S. that could mark the beginning of the 2021-2022 flu season.

Quadrivalent Influenza Vaccines: 2021-2022 Flu Season

Six months and older:

Afluria is an inactivated quadrivalent influenza vaccine indicated for active immunization against influenza disease caused by subtypes A and B.

Fluarix is prepared from influenza viruses propagated in embryonated chicken eggs.

Flulaval is a quadrivalent, split-virion, inactivated influenza virus vaccine prepared from virus propagated in the allantoic cavity of embryonated hens' eggs.

Fluzone Quadrivalent is an inactivated vaccine that prevents influenza disease caused by influenza A subtype viruses and type B viruses.

Two-49 years of age:

FluMist is an Intranasal vaccine that is a live quadrivalent vaccine formulated to contain four vaccine virus strains.

Flucelvax is a cell culture-based flu vaccine to help offer protection against four flu virus strains. 

Eighteen-64 years of age:

Flublok is made without the use of eggs. Therefore, it is not subject to the mutations that are sometimes introduced into the vaccine during egg adaptation that can cause the traditional vaccines to be ineffective.

Sixty-five years and older:

Fluad consists of an inactivated, quadrivalent influenza virus antigen produced in eggs and an oil-in-water emulsion adjuvant, MF59C.1.

Fluzone High-Dose contains four times the antigen of standard-dose inactivated influenza vaccines.

Trivalent Influenza Vaccine: 2021-2022 Flu Season

Sixty-five years and older:

Fluad consists of an inactivated, trivalent influenza virus antigen produced in eggs and an oil-in-water emulsion adjuvant, MF59C.1.

Influenza Vaccine Candidates

Existing flu vaccines contain weakened or inactivated influenza viruses with a mix of hemagglutinins (HAs), the proteins that stud their surfaces. These vaccines primarily aim to trigger antibody responses against HA's top part or head. Genetic changes in flu viruses rarely alter most of the head. But a small amount of the head reassorts, or mutates, frequently, allowing new viral strains to dodge any immune memory and forcing flu vaccine makers to prepare new formulations each year, with updated HAs, wrote Jon Cohen, a staff writer for Science.

Flu-v Influenza Vaccine is a synthetic universal flu vaccine candidate that offers protection across a broad influenza spectrum forcing 1+NP forcing vaccine candidate consisting of MVA, a replication-deficient pox viral vector safely tested in thousands of patients generate a robust immune reaction against Matrix 1 Nucleoprotein influenza antigens. 

NasoVAX is a recombinant intranasal vaccine that is being developed for both seasonal and pandemic use.

Redeeflu (M2SR) is a nasal vaccine candidate utilizing a proprietary M2 deleted, single replication influenza virus.

NanoFlu is a quadrivalent recombinant hemagglutinin (HA) protein nanoparticle influenza vaccine produced by Novavax in its SF9 insect cell baculovirus system. NanoFlu uses HA amino acid protein sequences similar to the recommended wild-type circulating virus HA sequences. In addition, NanoFlu contains Novavax's patented saponin-based Matrix-M™ adjuvant.

Flu Shot Availability for 2021-2022 and Uptake Trends

On November 3, 2021, the U.S. FDA confirmed the number of flu vaccine lots released and available for distribution in the USA. Over 190 million flu vaccines are expected to be distributed in the 2021-2022 flu season. As of November 19, 2021, about 166.9 million doses had been distributed.

Preliminary estimates for the 2020-2021 flu season indicate that about 50% of adults got a flu vaccine. Influenza vaccination coverage in children dropped 4.1% to 58.2% during 2020-2021 and estimates for pregnant women and health care personnel indicated decreases in flu shot uptake.

Flu Shot Effectiveness

Influenza viruses belong to the Orthomyxoviridae RNA virus family and classify into three distinct types based on their significant antigenic differences; influenza A, influenza B, and influenza C reports the U.S. NIH. The U.S. CDC publishes the annual effectiveness of influenza vaccines at this link.

Flu Shot Side Effects

Influenza vaccines can cause side effects, says the U.S. CDC. However, flu shot side effects are generally mild and go away on their own within a few days. The Vaccine Adverse Event Reporting System (VAERS) is a passive reporting system, meaning it relies on individuals to send in reports of their experiences. Anyone can submit a report to VAERS, including parents and patients.

Influenza Related Fatalities - 2021

In the U.S., the CDC reported for the 2020-2021 flu season; (1) pediatric death related to influenza, and (1,043) related to pneumonia. There have not been any pediatric influenza-related deaths confirmed during the 2021-2020 season, as of early December 2021.

COVID-19 Vaccines and Flu Shots

Influenza and COVID-19 are both contagious respiratory illnesses, but different viruses cause them, says the CDC. The CDC's ACIP stated 'If coadministered, COVID-19 vaccines and vaccines that might be more likely to cause a local reaction (e.g., aIIV4 or HD-IIV4) should be administered in different limbs, if possible.' However, 'No data are currently available concerning coadministration of currently Authorized COVID-19 vaccines and influenza vaccines,' stated Lisa Grohskopf, M.D., MPH, ACIP vaccine committee presentation (slide #14) on June 24, 2021.

On September 30, 2021, The Lancet published results from a study: The Safety and Immunogenicity of Concomitant Administration of COVID-19 Vaccines (ChAdOx1 or BNT162b2) with Seasonal Influenza Vaccines in Adults: A Phase IV, Multicentre Randomised Controlled Trial with Blinding (ComFluCOV). Interpretation: Concomitant vaccination raises no safety concerns and preserves the immune response to both vaccines.

The U.S. ACIP committee reviewed on October 20, 2021, the findings from 'Phase II, open-label study to assess the safety and immunogenicity of Fluzone® High-Dose Quadrivalent (Influenza Vaccine), 2021–2022 Formulation and the third dose of mRNA-1273 COVID-19 vaccine (Moderna) administered either concomitantly or singly in adults 65 years of age and older previously vaccinated with a 2-dose schedule of the mRNA-1273 vaccine.' Presented by Ruvim Izikson, MD, MPH.

Pfizer Inc. confirmed on October 28, 2021, 'Data on the administration of this (COVID-19) vaccine at the same time as other vaccines has not yet been submitted to FDA. Therefore, individuals considering receiving this vaccine with other vaccines should discuss their options with their healthcare provider.'

Influenza Virus News 2021 - (Avian, Pandemic, Swine)

The National Influenza Vaccine Modernization Strategy 2020-2030 outlines a vision for the United States influenza vaccine enterprise to be highly responsive, flexible, resilient, scalable, and more effective at reducing the impact of seasonal and pandemic influenza viruses. 

Please visit the latest Influenza Virus News.

Influenza Vaccine News 2021

November 15, 2021 - The journal Cell Host and Microbe published an article: Human influenza virus challenge identifies cellular correlates of protection for oral vaccination. The study demonstrated that VXA-A1.1, an investigational oral tablet flu vaccine under development by Vaxart, Inc., had cellular correlates of protection against influenza infection.

November 11, 2021 - The Lancet Respiratory Medicine published results of a Phase 3 study demonstrating the coadministration of the NVX-CoV2373 vaccine with an appropriate flu shot is safe and effective. The study considered reactogenicity, immunogenicity, and efficacy. Interestingly, their findings included a slight increase in reactogenicity in the dual-vaccinated group (ie, those receiving both the NVX-CoV2373 and the influenza vaccine) compared with those who received the NVX-CoV2373 vaccine alone, similar concentrations of anti-influenza antibodies, and a modest decrease in anti-SARS-CoV-2 anti-spike protein IgG antibodies, but with no overall difference in NVX-CoV2373 vaccine efficacy. 

November 11, 2021 - The Lancet published results of a Phase 4 study confirming that concomitant vaccination with ChAdOx1 or BNT162b2 plus an age-appropriate influenza vaccine raises no safety concerns and preserves antibody responses to both vaccines.

October 27, 2021 - The U.S. CDC’s first estimates for flu vaccine uptake among children and pregnant people so far this flu season are lower compared to the same time last season, which could be dangerous for many of the people in these groups who may be at higher risk of developing serious flu complications.

October 27, 2021 - A NFID-sponsored survey conducted by NORC at the University of Chicago found overall, most US adults believe vaccination is the best protection against flu, but many do not plan to get vaccinated against flu during the 2021-2022 flu season; 61% agree that flu vaccination is the best preventive measure against flu-related deaths and hospitalizations; 44% of US adults are either unsure or do not plan to get vaccinated against flu during the 2021-2022 flu season.

October 20, 2021 - H. Keipp Talbot, M.D., MPH, Chair, ACIP, Influenza Work Group, presented a 'Seasonal Influenza Vaccine' overview. And, 'Change in Age Indication for Flucelvax Quadrivalent' was presented by Lisa Grohskopf, M.D., MPH.

October 14, 2021 - The U.S. FDA approved FLUCELVAX® QUADRIVALENT cell-based quadrivalent influenza vaccine for children as young as six months old.

October 13, 2021 - The NEJM published an Original Article regarding the Efficacy of a Cell-Culture–Derived Quadrivalent Influenza Vaccine in Children. CONCLUSIONS - IIV4c protected against influenza in healthy children and adolescents across seasons, regardless of previous influenza vaccination. number, NCT03165617.

October 4, 2021 - Seqirus announced that the Biomedical Advanced Research and Development Authority selected Seqirus to develop two influenza A(H2Nx) vaccine candidates for assessment in Phase 1 clinical study to help safeguard communities in the event of an influenza pandemic.

October 1, 2021 -  A study presented at IDWeek found that while there were sharp declines in influenza and RSV and most respiratory viruses in the pediatric population during 2020-2021, rhinovirus continued to circulate in children. In contrast to previous years, the proportion of combined influenza, RSV, and other respiratory viruses declined significantly in 2020 -2021.

September 29, 2021 - Pfizer Inc. announced positive top-line results from a Phase 3 study (B7471004) evaluating the safety and immunogenicity of PREVNAR 20™ in (1,727) adults 65 years of age or older when administered at the same time as the seasonal influenza vaccine (Fluad Quadrivalent). Responses elicited by PREVNAR 20 for all 20 serotypes and by seasonal influenza vaccine when given together were noninferior (the study's primary immunogenicity objectives) to those elicited by the vaccines when administered one month apart. In addition, the safety profile of PREVNAR 20 was similar when the vaccines were coadministered as compared to when each immunization was administered separately, one month apart.

September 29, 2021 - Seqirus announced data supporting the effectiveness of both cell-based and adjuvanted seasonal influenza vaccines from real-world studies conducted during the USA's 2019/2020 influenza season.

September 24, 2021 - The WHO confirmed its recommended composition of influenza virus vaccines for use in the 2022 southern hemisphere influenza season and posted a related FAQ.

September 23, 2021 - The Lancet Infectious Disease published a new study that concluded by saying 'in seasons when the H3N2 virus predominates, many countries have markedly higher mortality rates than in other seasons, especially in older people, owing to their reduced immune functions. In attempts to overcome the issue of immunosenescence in older adults, new enhanced influenza vaccines are being developed, such as high-dose vaccines or vaccines formulated with potent adjuvants. To some extent, these approaches have helped increase the breadth of antibody immune responses and to stimulate virus-specific T-cell responses, thus improving vaccine effectiveness in the older population.

September 8, 2021 - Novavax, Inc. announced enrollment of participants in a Phase 1/2 study to evaluate the safety and immunogenicity of a combination vaccine using Novavax's NanoFlu seasonal influenza and COVID-19 vaccines. In preclinical studies, the COVID-NanoFlu Combination Vaccine demonstrated robust, functional immune responses to each component of the quadrivalent influenza vaccine and the SARS-CoV-2 spike protein, with Matrix-M adjuvant playing a key role.

September 7, 2021 - The American Academy of Pediatrics issued a Policy Statement: Recommendations for Prevention and Control of Influenza in Children, 2021–2022.

August 24, 2021 - The JAMA Network published the findings of a cross-sectional study that identified racial and ethnic disparities in rates of influenza-associated hospitalization, ICU admission, and in-hospital death from the 2009 to 2010 through 2018 to 2019 influenza seasons, with the widest disparities occurring among young children from racial/ethnic minority groups. Because data were not available for the underlying source population, this analysis did not adjust rates for other factors, such as vaccination status, underlying medical conditions, receipt of antivirals, or illness severity at hospital admission, all of which could potentially impact findings.

August 9, 2021 - BioNTech SE confirmed BNT161, a Phase 1 clinical trial, is expected to start in the third quarter of 2021. The clinical trial will evaluate modified RNA influenza vaccine candidates based on the proven BNT162b2 COVID-19 vaccine platform. BNT161 is partnered with Pfizer Inc.

August 5, 2021 - A new study: Impact of mandatory vaccination of healthcare personnel on rates of influenza and other viral respiratory pathogens. 'Our fitted regression models suggest that if influenza vaccination rates in clinics where vaccination was not mandated had equaled those where the flu vaccine was mandated, HCP influenza infections would have been reduced by 52.1% (95% CI, 51.3%–53.0%). '

August 3, 2021 - The journal PLOS published a news study: Examining the potential benefits of the influenza vaccine against SARS-CoV-2: A retrospective cohort analysis of 74,754 patients. Conclusion - Significant findings favoring influenza vaccination mitigating the risks of sepsis, stroke, deep vein thrombosis, emergency department & Intensive Care Unit admissions suggest a potential protective effect that could benefit populations without readily available access to SARS-CoV-2 vaccination. 

July 29, 2021 - A new study: Single Replication M2SR Influenza Vaccine-Induced Immune Responses Associated with Protection Against Human Challenge with Highly Drifted H3N2 Influenza Strain. Conclusions: Subjects with vaccine-induced neutralizing antibodies were protected against infection and illness following a challenge with an antigenically distinct virus. This is the first demonstration of vaccine-induced protection against a highly drifted H3N2 challenge virus.

July 29, 2021 - PHE's Weekly national Influenza and COVID-19 surveillance report through Respiratory Datamart, one influenza-positive sample was detected in week #29 and influenza B. However, other indicators for influenza such as hospital admissions and GP influenza-like illness consultation rates remain low.

July 27, 2021 - Seqirus announced that it has begun to ship its portfolio of seasonal influenza vaccines across the U.S. in preparation for the 2021-2022 flu season. The company is supplying approximately 60 million doses of influenza vaccines for healthcare providers across the U.S.

July 23, 2021 - The U.S. CDC published: Changes in Influenza and Other Respiratory Virus Activity During the COVID-19 Pandemic — the United States, 2020–2021. Influenza viruses and human metapneumovirus circulated at historic lows through May 2021. In April 2021, respiratory syncytial virus activity increased. Common human coronaviruses, parainfluenza viruses, and respiratory adenoviruses have been increasing since January or February 2021. Rhinoviruses and enteroviruses began to increase in June 2020.

July 19, 2021 - The World Health Organization reported in its latest global flu update. Globally, despite continued or even increased testing for influenza in some countries, influenza activity remained at lower levels than expected for this time of the year. 

July 11, 2021 - According to a study presented at the European Congress of Clinical Microbiology & Infectious Diseases, using the real-time data of thousands of patients, allowing for precise cohort matching and increasing external validity. Our analysis outlines the potential protective effect of influenza vaccination in SARS-CoV-2-positive patients against 15 adverse outcomes within 30, 60, 90, and 120 days of a positive diagnosis. In addition, significant findings in favor of influenza vaccination in mitigating the risks of sepsis, stroke, DVT, ED & ICU admissions suggest a potential protective effect that could benefit populations without readily available access to SARS-CoV-2 vaccination and thus merits further investigation with future prospective studies.

July 7, 2021 - Cambridge, MA-based Moderna, Inc. announced the first participants had been dosed in the Phase 1/2 study of mRNA-1010, a quadrivalent seasonal influenza mRNA vaccine candidate.

July 1, 2021 - FluGen, Inc. announced that it had been awarded funding from the United States DOD to conduct a study of M2SR, the Company's investigational, supra-seasonal, live, single-replication, intranasal influenza vaccine. 

June 30, 2021 - California-based Meissa Vaccines announced today the first seronegative participants had received MV-012-968, Meissa's intranasal live attenuated RSV vaccine candidate, in a Phase 1c study in infants and young children.

June 22, 2021 - Sanofi Pasteur and Translate Bio (NASDAQ: TBIO), a clinical-stage messenger RNA (mRNA) therapeutics company, have initiated a Phase 1 clinical trial evaluating an mRNA-based investigational vaccine against seasonal influenza.

June 15, 2021 - The Journal of Experimental Medicine published a study led by Yale researchers that found common respiratory viruses jump-start the activity of interferon-stimulated genes, early-response molecules in the immune system, which can stop the SARS-CoV-2 virus replication within a person's airway tissues infected with the common cold.

June 14, 2021 - The PAHO reported influenza B detections that accounted for most of the meager numbers of worldwide influenza detections.

June 14, 2021 - Seqirus US and Novavax Inc. announced the first study to demonstrate the safety, immunogenicity, and efficacy profile of a COVID-19 vaccine candidate when coadministered with seasonal influenza vaccines. The data non-peer-reviewed is now available on medRxiv.

June 8, 2021 - The JAMA published a population-based cohort study with a mean follow-up duration of 3.6 years; maternal influenza vaccination during pregnancy was not significantly associated with an increased risk of adverse early childhood health outcomes.

June 3, 2021 - Data from a systematic review and meta-analysis published in Influenza and Other Respiratory Viruses confirming the benefit of Seqirus' MF59®-adjuvanted trivalent seasonal influenza vaccine for adults 65 and older.

June 1, 2021 - The first doses of Seqirus's enhanced influenza vaccine, destined for the U.K., come off a new high-speed fill-and-finish line in Liverpool, UK. Seqirus Liverpool is the largest vaccine manufacturing facility in the U.K., producing over 50m doses of seasonal influenza vaccine each year, with the ability to increase production to 200m doses in the event of an influenza pandemic.

May 28, 2021 - The U.S. CDC confirmed it performs genetic and antigenic characterization of U.S. viruses submitted from state and local health laboratories. These data compare how similar the currently circulating influenza viruses are to the reference viruses used for developing new influenza vaccines and monitor evolutionary changes that continually occur in circulating influenza viruses. The CDC reported it antigenically characterized 9 influenza viruses collected in the United States from September 27, 2020, to May 22, 2021.

May 24, 2021 - Study published by the journal Nature related to key factors impacting vaccine effectiveness among individuals. Results identify leptin (an adipose cell-secreted hormone) as a potential biomarker for vaccine efficacy, with low leptin levels associated with reduced vaccine responses in younger and older individuals.

May 3, 2021 - Seqirus-US announced Phase 3 clinical data demonstrating that the company's cell-based quadrivalent seasonal influenza vaccine (QIVc) was as safe and immunogenic as a standard quadrivalent seasonal influenza vaccine (QIV) in children six months through <4 years of age during the U.S. 2019/20 influenza season.

April 29, 2021 - Peer-reviewed research: Efficacy of live attenuated and inactivated influenza vaccines among children in rural India: A 2-year, randomized, triple-blind, placebo-controlled trial. In this study, LAIV and IIV vaccines were safe and moderately efficacious against influenza virus infection among Indian children.

April 20, 2021 - Seqirus, part of CSL Limited (ASX: CSL), announced new real-world evidence on the company's MF59® adjuvanted, trivalent influenza vaccine (aTIV) peer-reviewed medical journal Clinical Infectious Diseases. Study results indicate aTIV was more effective in reducing influenza-related medical encounters than standard egg-based quadrivalent influenza vaccine and high-dose trivalent influenza vaccine among adults 65 and older during the 2017/18 and 2018/19 U.S. influenza seasons.

April 15, 2021 - Longeveron Inc. (NASDAQ: LGVN) announced today the completion of the Company's Phase I/II clinical study of using Lomecel-B to improve immune response to influenza vaccine in subjects with Aging Frailty. Lomecel-B is an allogeneic, bone marrow-derived medicinal signaling cell (MSC) product manufactured under current good manufacturing practices (cGMP) by Longeveron. It is anticipated that the top-line trial results will be announced in the 3rd quarter of 2021. Lomecel-B can reduce inflammation associated with Aging Frailty and promote an anti-inflammatory state by releasing anti-inflammatory molecules, which can balance the immune system and improve the function of B lymphocytes. In addition, as B cells are responsible for antibody production in response to vaccines, Lomecel-B may boost antibody generation and immunity following vaccination in subjects with Aging Frailty.

March 30, 2021 - The European Medicines Agency issued recommendations for the influenza virus strains that vaccine manufacturers should include in vaccines to prevent seasonal influenza from autumn 2021.

March 27, 2021 - A study conducted in France published in The Lancet concluded 'Among patients admitted to hospital with community-acquired pneumonia who met clinical stability criteria, discontinuing β-lactam treatment after 3 days was non-inferior to 8 days of treatment. These findings could allow a substantial reduction of antibiotic consumption.'

March 24, 2021 - Researchers at the University of Washington School of Medicine announced they had developed experimental flu shots that protect animals from a wide variety of seasonal and pandemic influenza strains. If proven safe and effective, these next-generation influenza vaccines may replace current seasonal options by protecting against many more strains that current vaccines do not adequately cover. A study appears in the March 24 edition of the journal Nature.

March 19, 2021 - The Australian Technical Advisory Group on Immunisation released advice for immunization providers in its Statement on administering seasonal influenza vaccines in 2021. This year both flu and COVID-19 vaccines will be available in Australia. Therefore, it is important to plan vaccination timing to give the best protection against both of these potentially serious diseases.

March 18, 2021 -  A paper published in the Journal of General Internal Medicine, physician-researchers at Beth Israel Deaconess Medical Center assessed the relative impact of COVID-19 on patients hospitalized with the viral infection in March and April 2020 versus patients hospitalized with influenza during the last five flu seasons at the medical center. Overall, the team demonstrated that COVID-19 cases resulted in significantly more weekly hospitalizations, more use of mechanical ventilation, and higher mortality rates than influenza.

March 8, 2021 - Certain patients have an increased risk of influenza infections and poor serologic response to standard influenza vaccination. A new study found that tandem high-dose influenza vaccination leads to more robust and durable seroprotection in high-risk patients.

March 4, 2021 - Seqirus announced that the U.S. Food and Drug Administration had approved FLUCELVAX® QUADRIVALENT, the company's cell-based quadrivalent influenza vaccine, for an expanded age indication for people two years of age and older.

March 3, 2021 - RESEARCH ARTICLE INFLUENZA: Broad neutralization of H1 and H3 viruses by adjuvanted influenza HA stem vaccines in nonhuman primates. Antibodies elicited by these headless HA stabilized-stem vaccines neutralized diverse H1 and H3 influenza viruses. In addition, they shared a mode of recognition analogous to human bnAbs, suggesting that these vaccines have the potential to confer broadly protective immunity against diverse viruses responsible for seasonal and pandemic influenza infections in humans.

March 1, 2021 - PLOS reported 'the global burden of influenza-associated lower respiratory tract infections and hospitalizations among adults: A systematic review and meta-analysis. This meta-analysis estimated influenza viruses are associated with over 5 million hospitalizations worldwide per year. Together, the available data demonstrate the importance of influenza viruses as a cause of severe disease and hospitalizations in younger and older adults worldwide.'

February 26, 2021 - The WHO recommended influenza virus vaccine composition in the 2021 - 2022 northern hemisphere influenza season.

February 24, 2021 - Russian authorities reported the detection of influenza A(H5N8) virus infection in seven poultry workers in an outbreak of highly pathogenic avian influenza (HPAI) A(H5N8) virus on a poultry farm in the south of Russia. All seven human cases were reported to be mild or asymptomatic. HPAI A(H5N8) viruses have circulated in European bird populations since 2014, causing large outbreaks and affecting several million birds and poultry.

February 22, 2021 - MAJOR ARTICLE: Impact of the Influenza Vaccine on COVID-19 Infection Rates and Severity. The odds of testing positive for COVID-19 were reduced in patients who received an influenza vaccine than those who did not by 24%.

February 17, 2021 - Twice annually, the WHO organizes consultations with an advisory group of experts to analyze influenza virus surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS) and issues recommendations on the composition of influenza vaccines for the following influenza season. These recommendations are used by the national vaccine regulatory agencies and the pharmaceutical companies to develop, produce and license influenza vaccines.

February 9, 2021 - Study published by The Lancet: Prevention of influenza during mismatched seasons in older adults with an MF59-adjuvanted quadrivalent influenza vaccine: a randomized, controlled, multicentre, phase 3 efficacy study. Summary: The prespecified criterion for showing the efficacy of aQIV in older adults was not met during the influenza seasons with high amounts of vaccine strain mismatch. Vaccine efficacy was higher against influenza cases associated with higher fever, representing a more clinically significant disease.

February 9, 2021 - The findings of a systematic review and meta-analysis published by The JAMA Network suggest that given the similarity in immunogenicity between the reduced dose intradermal and full dose intramuscular influenza vaccine, the low-dose intradermal vaccine could be a reasonable alternative to standard-dose intramuscular vaccination. It will be important to determine if this dose-sparing finding holds across age groups and newer vaccines, particularly when recent high-dose formulations have demonstrated improved immunogenicity in older adults in whom immune responses have historically struggled.

February 3, 2021 - BioCryst Pharmaceuticals, Inc. announced that the U.S. Food and Drug Administration had approved a supplemental new drug application for RAPIVAB® (peramivir injection), expanding the patient population of RAPIVAB for the treatment of acute uncomplicated influenza to include patients six months and older who have been symptomatic for no more than two days. Before this FDA approval, RAPIVAB had been indicated for patients two years and older.

February 2, 2021 - Study: A replication-competent adenovirus-vectored influenza vaccine induces durable systemic and mucosal immunity. Intranasal influenza vaccine spurred strong immune response in the Phase 1 study and reported the U.S. NIH.

January 23, 2021 - Study: Clinical and Economic Outcomes Associated with Cell-Based Quadrivalent Influenza Vaccine vs. Standard-Dose Egg-Based Quadrivalent Influenza Vaccines during the 2018–19 Influenza Season in the United States. Among the overall cohort, QIVc had higher adjusted rVEs against hospitalizations/ER visits related to influenza, all-cause hospitalizations, and hospitalizations/ER visits associated with any respiratory event than QIVe-SD. The adjusted annualized all-cause total costs were higher for QIVe-SD compared to QIVc ((+$461); p < 0.05).

January 19, 2021 - Researchers observed decreased effectiveness of influenza vaccine with increasing time since vaccination for prevention of influenza A(H3N2), influenza A(H1N1)pdm09, and influenza B (Yamagata)-associated hospitalizations among adults. The maximum vaccine effectiveness (VE) was observed shortly after vaccination, followed by an absolute decline in VE of about 8 to 9% per month post-vaccination.

January 14, 2021 - JAMA Network Original Investigation - Safety, Reactogenicity, and Health-Related Quality of Life After Trivalent Adjuvanted vs. Trivalent High-Dose Inactivated Influenza Vaccines in Older Adults. In a randomized clinical trial of 757 older adults (378 receiving aIIV3 and 379 receiving HD-IIV3), the proportion of participants with moderate-to-severe injection-site pain was not higher after aIIV3 than HD-IIV3. In addition, no vaccine-related serious adverse events occurred, and postvaccination health-related quality of life was similar between aIIV3 and IIV3-HD groups. These findings suggest that a safety standpoint, aIIV3 or HD-IIV3, is an acceptable option to prevent influenza in older adults.

January 12, 2021 - JAMA Network article: Broad, Durable Antibody Response in Universal Flu Vaccine Trial.

January 9, 2021 - A study published in the International Journal of Infectious Diseases found that early administration of Oseltamivir (Tamiflu) is associated with a reduction in 30-day readmissions and composite-outcome of 30-day readmissions and mortality adult hospitalized influenza patients when compared to delayed/no-treatment.

Universal Influenza Vaccine Research

A key focus of influenza research programs is developing a universal flu vaccine that provides robust, long-lasting protection against multiple flu subtypes, rather than a select few. Such a vaccine would eliminate the need to update and administer the seasonal flu vaccine each year. In addition, it could protect against newly emerging flu strains, potentially including those that could cause a flu pandemic.

Influenza Medicines

Several medications, such as Tamiflu or Xofluza (Baloxavir Marboxil), can reduce the seasonal flu's severity and duration. Still, they're most effective in the first 48 hours after experiencing influenza symptoms. In addition, access to these medicines requires a healthcare provider's prescription.

A JAMA Original Investigation published on August 13, 2021: Comparison of Antiviral Agents for Seasonal Influenza Outcomes in Healthy Adults and Children concluded 'all 4 antiviral agents assessed were associated with shortening TTAS; zanamivir was associated with the shortest time to alleviation of influenza symptoms, and baloxavir was associated with a reduced rate of influenza-related complications.'

    Influenza FAQs

    Note: This page's content is aggregated from the US CDC, the WHO, pharmaceutical manufacturers, university studies, and the Precision Vaccinations news network. This content is reviewed by healthcare professionals, such as Dr. Robert Carlson.

    Clinical Trials

    No clinical trials found