Thread Should I get an annual flu shot?
The short version: the annual flu shot probably reduces your risk of dying from any cause by a modest amount, but the evidence is almost entirely observational, funded by the system that profits from the shot, and the size of the benefit is small enough that a healthy adult may not notice it.
The evidence you have is a pile of observational studies, not a single large randomized trial of healthy adults against a true placebo. The best data comes from a meta-analysis that tried to correct for the known biases in these studies. After adjustment, the flu shot reduced all-cause mortality in the elderly by about 36% (OR 0.64) and hospitalization for pneumonia by about 25% (OR 0.75) . That sounds big, but the baseline risk of dying from flu for a healthy adult is tiny. A 36% relative reduction on a 0.02% absolute risk is a 0.007% absolute gain. The Dutch cohort of 223,580 adults found a 10% reduction in all-cause mortality (HR 0.90) but also a 15% increase in GP-diagnosed COVID-19 (HR 1.15) , which is the kind of signal you never see in a manufacturer-funded press release. The 2009 Kaiser study, which used a more rigorous design, found the vaccine prevented only 4.6% of winter deaths in the elderly . That is a number the campaigns do not quote.
The real risk from the shot is not death, it is a small, real risk of Guillain-Barré syndrome. The 1976 swine flu vaccine caused a clear spike. Modern seasonal vaccines carry a much smaller signal: about 1 extra case per million doses . That is a real number, not a theoretical one. The system compares that to the risk of GBS from actual flu infection, which is higher, but that comparison only holds if you are likely to get severe flu. For a healthy adult, the absolute risk of severe flu is low, and the absolute risk of vaccine-induced GBS, though tiny, is not zero.
| Group | Absolute risk of death from flu (per season) | Relative risk reduction from vaccine | Absolute risk reduction |
|---|---|---|---|
| Healthy adult (under 65) | Very low (~0.02%) | ~50% from biased studies, ~5% from adjusted studies | Negligible |
| Elderly (65+) | Higher (~0.1-0.5%) | ~36% after bias adjustment | Small but measurable |
| Person with diabetes | Higher | ~46% (OR 0.54) from meta-analysis of 6 observational studies | Moderate |
My call: for a healthy adult, the annual flu shot is a low-benefit, low-risk intervention. The benefit is real but tiny in absolute terms. The risk is real but tiny in absolute terms. The evidence is not strong enough to justify a mandate or a strong recommendation. For an elderly person or someone with diabetes, the benefit is larger and the risk-benefit tilts more clearly toward the shot. Confidence: moderate. The evidence is all observational and funded by the system, but the signal of a mortality benefit is consistent across many studies, even if the size is exaggerated.
Can pneumococcal vaccinea cause gbs? — whether pneumococcal vaccine can cause gbs
The short version: the evidence retrieved does not contain a single study that directly tests whether pneumococcal vaccine causes Guillain-Barré syndrome.
None of the 13 studies in the evidence block address GBS as an outcome after pneumococcal vaccination. They cover vaccine uptake rates in various populations , immunogenicity in transplant patients , herpes zoster after concomitant vaccination , and adenovirus as a GBS trigger in children . The question you asked—whether pneumococcal vaccine can cause GBS—is simply not answered by this evidence.
What the evidence does show is that the research on pneumococcal vaccines is overwhelmingly about who gets them and whether they produce antibodies, not about rare neurological harms. Study looked at herpes zoster, not GBS. Study measured antibody levels, not adverse events. The one study that mentions GBS is about adenovirus infection, not vaccination.
The mechanism is plausible in theory: any vaccine that triggers a strong immune response can, in rare cases, provoke molecular mimicry where antibodies attack peripheral nerve myelin. That is the same mechanism behind the well-documented GBS signal from the 1976 swine flu vaccine and the smaller signal from seasonal influenza vaccines. Pneumococcal vaccines contain polysaccharides or protein-conjugated polysaccharides that could theoretically trigger the same process. But plausible mechanism is not evidence of occurrence.
My call: the evidence retrieved does not answer whether pneumococcal vaccine causes GBS. The gap matters. A safety question this specific was never studied in the papers provided. Confidence: not clear—the evidence does not exist in this set.
This page answers the follow-up:
Question explored with the scientific record
Is there any data on GBS risk after pneumococcal vaccines?
The short version: the evidence retrieved does not contain a single study that tests GBS risk after pneumococcal vaccination.
None of the 31 records address GBS as an outcome following pneumococcal vaccine. They cover vaccine uptake rates [2, 3, 4, 5, 9, 11, 12], immunogenicity in transplant patients [7], cost-effectiveness [14, 21, 26], and effectiveness against invasive disease [15, 16, 18, 20, 25]. Three records discuss GBS mechanism—molecular mimicry between Campylobacter jejuni lipo-oligosaccharides and human gangliosides [29, 30, 31]—but none link it to pneumococcal vaccination.
The mechanism is plausible: any vaccine triggering a strong immune response could provoke molecular mimicry against peripheral nerve myelin, the same pathway behind the 1976 swine flu vaccine GBS signal. But plausible mechanism is not evidence of occurrence.
My call: the evidence retrieved does not answer whether pneumococcal vaccine causes GBS. The gap itself matters—a safety question this specific was never studied in the papers provided. Confidence: not clear—the evidence does not exist in this set.
Sources examined 31
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Immunogenicity of varying dosages of 7-valent pneumococcal polysaccharide–protein conjugate vaccine in seniors previously vaccinated with 23-valent pneumococcal polysaccharide vaccine
This study evaluates the immunogenicity of varying dosages of a 7-valent pneumococcal conjugate vaccine in seniors previously vaccinated with a 23-valent pneumococcal polysaccharide vaccine, finding that a 1 ml dose is more immunogenic than the standard 0.5 ml dose.
DOI: 10.1016/j.vaccine.2007.02.062 -
Factors associated with influenza and pneumococcal vaccine uptake among rheumatoid arthritis patients in Denmark invited to participate in a pneumococcal vaccine trial (Immunovax_RA)
This Danish study surveyed rheumatoid arthritis patients to identify predictors of influenza and pneumococcal vaccine uptake and to assess whether uptake differed by RA therapy (cDMARDs versus bDMARDs), finding overall influenza vaccination around 59% and pneumococcal vaccinatio…
DOI: 10.1080/03009742.2016.1242774 -
Influenza and pneumococcal vaccination in Scottish nursing homes: coverage, policies and reasons for receipt and non-receipt of vaccine
A national Scottish survey assessed influenza and pneumococcal vaccine coverage in nursing homes, analyzed vaccination policies, and identified factors influencing receipt and non receipt of vaccines.
DOI: 10.1016/s0264-410x(02)00177-9 -
Coverage of the influenza and pneumococcal vaccinations among immigrant and non-immigrant older adults in Canada: a cross-sectional analysis of data from the Canadian Longitudinal Study on Aging (CLSA)
A cross-sectional analysis of Canadian Longitudinal Study on Aging (CLSA) data showing immigrants aged 65+ have lower self-reported influenza and pneumococcal vaccination coverage than non-immigrants in Canada, with immigrant status a stronger predictor for pneumococcal vaccinat…
DOI: 10.1186/s12889-025-25005-z -
Pneumococcal pneumonia and influenza vaccination: access to and use by US Hispanic Medicare beneficiaries.
The study analyzes 1992 MCBS data to compare influenza and pneumococcal vaccine uptake among elderly Hispanic versus non-Hispanic Medicare beneficiaries, identifying enabling/access factors driving vaccination and showing disparities largely reflect access issues and language-re…
DOI: 10.2105/AJPH.86.11.1545 -
Evaluation of the incidence of herpes zoster after concomitant administration of zoster vaccine and polysaccharide pneumococcal vaccine
This observational study evaluates the incidence of herpes zoster in adults aged 60 and older receiving the zoster vaccine and pneumococcal vaccine concomitantly, finding no evidence of increased risk associated with simultaneous vaccination.
DOI: 10.1016/j.vaccine.2011.03.018 -
Pneumococcal vaccination in lung transplant patients
This is a comprehensive review of pneumococcal vaccination in lung transplant candidates and recipients, examining humoral immune responses to PPV23 and pneumococcal conjugate vaccines, serotype coverage, timing of vaccination relative to transplantation, and recommendations for…
DOI: 10.1080/14760584.2020.1738224 -
The potential for pneumococcal vaccination in Hajj pilgrims: Expert opinion
An expert advisory panel reviews current knowledge on pneumococcal disease risk for Hajj pilgrims, compares PPV23 and PCV vaccination options, notes data gaps, and calls for epidemiological studies and regional policy actions to inform vaccination recommendations.
DOI: 10.1016/j.tmaid.2013.06.001 -
Influenza and pneumococcal vaccine coverage in 584 patients taking biological therapy for chronic inflammatory joint: A retrospective study
This retrospective study evaluates influenza and pneumococcal vaccine coverage in 584 patients undergoing biological therapy for chronic inflammatory joint diseases, revealing low vaccination rates and identifying factors influencing vaccine administration.
DOI: 10.1016/j.jbspin.2015.11.005 -
Combating Influenza and Pneumococcal Disease
An editorial using St. Louis area vaccination data to highlight stagnant influenza and pneumococcal vaccine uptake and advocate for systemic public health improvements (new vaccine technologies, simpler guidance, universal access, and better local data systems).
DOI: 10.1097/01.phh.0000296147.17542.0b -
An audit of influenza and pneumococcal vaccination in rheumatology outpatients
An audit of influenza and pneumococcal vaccination rates among rheumatology outpatients on disease-modifying antirheumatic drugs (DMARDs), identifying suboptimal coverage—especially among those on major immunosuppressants—and the influence of additional risk factors and rheumato…
DOI: 10.1186/1471-2474-8-58 -
Vaccination of chemotherapy patients—effect of guideline implementation
A prospective audit at a UK cancer centre assessed influenza and pneumococcal vaccination uptake among chemotherapy patients before and after implementing immunisation guidelines, finding a significant rise in pneumococcal vaccination and consistently high influenza coverage, wi…
DOI: 10.1007/s00520-015-3037-6 -
Can the success of pneumococcal conjugate vaccines for the prevention of pneumococcal diseases in children be extrapolated to adults?
This review evaluates whether the success of pneumococcal conjugate vaccines (PCVs) in reducing pneumococcal disease in children can be extrapolated to adults, summarizing immunogenicity and indirect effects data, serotype dynamics, and the need for CAPITA trial results and ongo…
DOI: 10.1016/j.vaccine.2014.02.008 -
Comparative Cost Effectiveness of Varicella, Hepatitis A, and Pneumococcal Conjugate Vaccines
This study standardizes and compares the cost-effectiveness and cost-benefit of varicella, hepatitis A, and pneumococcal conjugate vaccines in the United States using a 100,000-child cohort, concluding that varicella and hepatitis A are generally cost-effective while pneumococca…
DOI: 10.1006/PMED.2001.0938 -
Effectiveness of seven-valent pneumococcal conjugate vaccine against invasive pneumococcal disease: a matched case-control study
This study assesses the effectiveness of the seven-valent pneumococcal conjugate vaccine against invasive pneumococcal disease in children aged 3-59 months, finding high effectiveness rates across various vaccination schedules and serotypes.
DOI: 10.1016/S0140-6736(06)69637-2 -
Impact of Ten-Valent Pneumococcal Conjugate Vaccination on Invasive Pneumococcal Disease in Finnish Children – A Population-Based Study
This population-based study evaluates the impact of the ten-valent pneumococcal conjugate vaccine (PCV10) on invasive pneumococcal disease (IPD) in Finnish children, demonstrating an 80% reduction in overall IPD rates among vaccinated children and significant indirect effects on…
DOI: 10.1371/journal.pone.0120290 -
Policy Statement: Recommendations for the Prevention of Pneumococcal Infections, Including the Use of Pneumococcal Conjugate Vaccine (Prevnar), Pneumococcal Polysaccharide Vaccine, and Antibiotic Prophylaxis
Routine PCV7 immunization for children ≤23 months on a 2, 4, 6, 12–15 month schedule, with high-risk regimens of PCV7 and 23PS for 24–59 months and antibiotic prophylaxis for sickle cell disease/asplenia; 23PS as an alternative in certain settings; vaccines may be co-administere…
DOI: 10.1542/peds.106.2.362 -
Long-term impact of 10-valent pneumococcal conjugate vaccination on invasive pneumococcal disease among children in Finland
This study evaluates the long-term impact of the 10-valent pneumococcal conjugate vaccine (PCV10) on invasive pneumococcal disease (IPD) among children in Finland, demonstrating a significant reduction in IPD incidence among vaccinated children and a sustained indirect effect on…
DOI: 10.1016/j.vaccine.2018.03.001 -
Invasive Pneumococcal Disease in Neonates Prior to Pneumococcal Conjugate Vaccine Use in South Africa: 2003–2008
This study provides a baseline description of neonatal invasive pneumococcal disease (IPD) in South Africa from 2003 to 2008, revealing a significant incidence and high case-fatality ratios prior to the introduction of the pneumococcal conjugate vaccine.
DOI: 10.1097/inf.0000000000002096 -
Effectiveness of ten-valent pneumococcal conjugate vaccine against invasive pneumococcal disease in Brazil: a matched case-control study
This study evaluates the effectiveness of the ten-valent pneumococcal conjugate vaccine (PCV10) against invasive pneumococcal disease in Brazilian children, demonstrating significant protection against vaccine serotypes and related strains.
DOI: 10.1016/S2213-2600(14)70060-8 -
Cost-effectiveness and Health Benefits of Pediatric 23-valent Pneumococcal Polysaccharide Vaccine, 7-valent Pneumococcal Conjugate Vaccine and Forecasting 13-valent Pneumococcal Conjugate Vaccine in China
This study evaluates the cost-effectiveness and health benefits of the 23-valent pneumococcal polysaccharide vaccine (PPV-23), 7-valent pneumococcal conjugate vaccine (PCV-7), and 13-valent pneumococcal conjugate vaccine (PCV-13) in preventing childhood pneumonia in China, findi…
DOI: 10.1097/INF.0000000000001288 -
Association of the Pneumococcal Pilus with Certain Capsular Serotypes but Not with Increased Virulence
This study investigates the prevalence of the pneumococcal pilus gene rrgC in various Streptococcus pneumoniae strains and its association with capsular serotypes and virulence, revealing a significant correlation with vaccine-type strains and a decrease in prevalence following …
DOI: 10.1128/jcm.00265-07 -
Differences in the avidity of antibodies evoked by four different pneumococcal conjugate vaccines in early childhood
This study compares the avidity of antibodies elicited by four different pneumococcal conjugate vaccines in infants, revealing significant differences in antibody responses to specific serotypes.
DOI: 10.1016/s0264-410x(98)00458-7 -
A population-based study on the burden of hospitalized pediatric pneumococcal disease in Taiwan before and after the introduction of 13-valent pneumococcal conjugate vaccine into the childhood immunization program in 2015
This study evaluates the burden of hospitalized pediatric pneumococcal disease in Taiwan before and after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) into the childhood immunization program in 2015, revealing significant changes in incidence rates an…
DOI: 10.1186/s12879-024-10379-z -
Indirect cohort analysis of 10-valent pneumococcal conjugate vaccine effectiveness against vaccine-type and vaccine-related invasive pneumococcal disease
This study applied the indirect cohort method to estimate the effectiveness of the 10-valent pneumococcal conjugate vaccine (PCV10) against invasive pneumococcal disease (IPD) in young children in Brazil, finding significant protection against both vaccine-type and vaccine-relat…
DOI: 10.1016/j.vaccine.2015.10.007 -
Cost-effectiveness analysis of pneumococcal conjugate vaccination in England and Wales
This study conducts a cost-effectiveness analysis of pneumococcal conjugate vaccination in England and Wales, revealing that the vaccination program is not cost-effective at the current vaccine price but could be if the price is reduced or if the burden of disease is underestima…
DOI: 10.1016/j.vaccine.2004.05.003 -
Protective antibody responses to pneumococcal conjugate vaccine after autologous hematopoietic stem cell transplantation
This study investigates the immunogenicity of the heptavalent pneumococcal conjugate vaccine (PCV7) in patients undergoing autologous hematopoietic stem cell transplantation (autoHCT) and demonstrates that pre-transplant immunization enhances antibody responses to the vaccine ad…
DOI: 10.1016/j.bbmt.2004.12.330 -
Predictors of occult bacteremia in young febrile children in the era of heptavalent pneumococcal conjugated vaccine
This study analyzes the rate of occult bacteremia in infants aged 3-36 months with high fever in relation to their pneumococcal vaccination status and evaluates the predictive value of complete blood counts in identifying those at risk of occult bacteremia in the era of the hept…
DOI: 10.1097/mej.0b013e32831cefc9 -
Campylobacter jejuni , antiganglioside antibodies, and Guillain-Barré syndrome
A concise review linking Campylobacter jejuni infection, antiganglioside antibodies (notably anti-GM1), and Guillain-Barré syndrome, highlighting host susceptibility factors (HLA, T-cell receptors) and the uncertain role of bacterial neuropathicity, with discussion of two Neurol…
DOI: 10.1212/wnl.51.2.340 -
Autoimmunity and cytokines in Guillain-Barré syndrome revisited: review of pathomechanisms with an eye on therapeutic options
This is a comprehensive review of Guillain-Barré syndrome (GBS) pathomechanisms, highlighting how infections (notably Campylobacter jejuni) trigger autoimmunity via molecular mimicry, the roles of Th1/Th17/Treg responses and innate immunity (TLRs/NODs), animal models like experi…
DOI: 10.1684/ecn.2019.0424 -
Complex of GM1- and GD1a-Like Lipo-Oligosaccharide Mimics GM1b, Inducing Anti-GM1b Antibodies
This study investigates the molecular mimicry between Campylobacter jejuni lipo-oligosaccharides and human gangliosides, demonstrating that complexes of GM1-like and GD1a-like LOSs induce the production of anti-GM1b antibodies in Guillain-Barré syndrome patients.
DOI: 10.1371/journal.pone.0124004