Study findings updated . AI-assisted evidence summary, not individual medical advice or a clinician endorsement.
THE SHORT VERSION
What’s worth knowing.
The key findings, what they mean, and the context that matters.
THE HEADLINE TAKEAWAY55% lower oddsCOVID hospitalization odds with the 2025-2026 shot vs no shot this season, US adults
The 2025-2026 shot was linked to 55% lower COVID hospitalization odds.
In US adults with healthy immune systems seen for COVID-like illness from September to December 2025, getting the 2025-2026 shot was linked to 55% lower odds of COVID hospitalization compared with skipping this season's dose, regardless of earlier shots. Effectiveness was 53% in people 65 and older and 50% against emergency or urgent care visits.
Nearly everyone now has some immunity from past shots or infections, so the real question was whether a fresh shot still adds anything. This early look says it does, for younger and older adults alike. Early observational estimate in adults with healthy immune systems in 7 states, measured soon after vaccination, so it cannot show how long protection lasts or prove cause.
See the evidence
A test-negative case-control study (comparing past vaccination in people testing positive vs negative) using health records from hospitals and emergency departments in 7 US states, September–December 2025.
From the study: “Estimated VE against COVID-19-associated hospitalization was 55%”
55% lower odds
Wiegand, Ryan E et al.. Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design.. JAMA network open. 2026.
From the study: “and against hospitalization was 53%”
55% lower odds
Wiegand, Ryan E et al.. Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design.. JAMA network open. 2026.
From the study: “Estimated VE against COVID-19-associated ED/UC encounters was 50%”
55% lower odds
Wiegand, Ryan E et al.. Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design.. JAMA network open. 2026.
Vaccines may have prevented 19.8 million deaths in their first year.
19.8 million livesEstimated deaths averted worldwide in vaccines' first year, using excess deaths
A model of 185 countries estimated that from December 2020 to December 2021, vaccines averted 19.8 million COVID deaths when counting all excess deaths, or 14.4 million using official COVID death counts. That is 63% fewer deaths than the 31.4 million the model predicted in a world without vaccines.
It puts the rollout's benefit in human terms. The same model found low-income countries, with few doses, could have averted an extra 45% of deaths had each reached a modest 20% coverage target. These are computer-model estimates of a no-vaccine world, not counted deaths; a later analysis using more cautious methods estimated far fewer lives saved.
See the evidence
A mathematical modeling study fitted to reported COVID deaths and excess deaths in 185 countries and territories from December 2020 to December 2021.
From the study: “This estimate rose to 19·8 million (95% Crl 19·1-20·4) deaths from COVID-19 averted when we used excess deaths as an estimate of the true extent of the pandemic”
19.8 million lives
Watson OJ et al. Global impact of the first year of COVID-19 vaccination: a mathematical modelling study. The Lancet. Infectious diseases. 2022.
From the study: “we estimated that vaccinations prevented 14·4 million (95% credible interval [Crl] 13·7-15·9) deaths from COVID-19 in 185 countries and territories”
19.8 million lives
Watson OJ et al. Global impact of the first year of COVID-19 vaccination: a mathematical modelling study. The Lancet. Infectious diseases. 2022.
Myocarditis after Pfizer shots was rare, and more common after COVID.
2.7 per 100,000Extra myocarditis cases after Pfizer shots; COVID infection added 11.0 per 100,000
In Israel's largest health system, people who got the Pfizer-BioNTech vaccine had 2.7 extra cases of myocarditis (heart muscle inflammation) per 100,000 within 42 days, compared with matched unvaccinated people. COVID infection was linked to 11.0 extra cases per 100,000 versus matched uninfected people. Vaccine-linked cases were mostly young men: median age 25, 90.9% male.
Myocarditis is the best-known rare risk of mRNA vaccines. The virus itself also raised risks of blood clots in the lungs, heart attack and irregular heartbeat, which the vaccine was not found to raise. Observational data from early in the rollout; vaccine and infection risks came from separate comparisons, and young men carried most of the vaccine-linked risk.
See the evidence
A matched cohort study in Israel's largest health organization comparing 884,828 vaccinated people with matched unvaccinated people, plus a separate infected-versus-uninfected comparison.
From the study: “Vaccination was most strongly associated with an elevated risk of myocarditis (risk ratio, 3.24; 95% confidence interval [CI], 1.55 to 12.44; risk difference, 2.7 events per 100,000 persons”
2.7 per 100,000
Barda N et al. Safety of the BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Setting. The New England journal of medicine. 2021.
From the study: “SARS-CoV-2 infection was associated with a substantially increased risk of myocarditis (risk ratio, 18.28; 95% CI, 3.95 to 25.12; risk difference, 11.0 events per 100,000 persons”
2.7 per 100,000
Barda N et al. Safety of the BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Setting. The New England journal of medicine. 2021.
From the study: “Among the 21 persons with myocarditis in the vaccinated group, the median age was 25 years (interquartile range, 20 to 34), and 90.9% were male.”
2.7 per 100,000
Barda N et al. Safety of the BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Setting. The New England journal of medicine. 2021.
Vaccinated veterans developed long COVID far less often after Omicron infection.
3.50 in 100Vaccinated veterans with long COVID a year after Omicron; 7.76 in 100 if unvaccinated
Among US veterans infected in the Omicron era, 3.50 in 100 vaccinated people developed long COVID (lasting health problems after infection) within a year, versus 7.76 in 100 unvaccinated people, after adjusting for differences between groups. In the researchers' statistical breakdown, 71.89% of the pandemic-long decline in long COVID was linked to vaccination, the rest to virus and era changes.
Long COVID can affect the heart, lungs, brain and energy levels for months. Vaccination was linked to far fewer cases, but even vaccinated people still faced a real risk. Observational study of US veterans, who are not typical of all Americans; vaccinated and unvaccinated people may differ in ways the statistics could not capture.
See the evidence
A Department of Veterans Affairs health-records study of 441,583 veterans infected from March 2020 to January 2022 and 4,748,504 uninfected comparison veterans, followed one year.
From the study: “and 3.50 events per 100 persons (95% CI, 3.31 to 3.71) during the omicron era”
3.50 in 100
Xie Y et al. Postacute Sequelae of SARS-CoV-2 Infection in the Pre-Delta, Delta, and Omicron Eras. The New England journal of medicine. 2024.
Vaccination during pregnancy was linked to fewer COVID hospitalizations in babies.
52% effectiveProtection from mom's pregnancy shots against infant COVID hospitalization
At 30 US children's hospitals in 22 states, babies under 6 months hospitalized with COVID were compared with babies hospitalized for other reasons. Two mRNA doses during pregnancy were linked to 52% lower odds of the baby's COVID hospitalization, and 69% when given after 20 weeks of pregnancy. Two babies died of COVID; neither mother had been vaccinated in pregnancy.
Babies this young cannot get COVID vaccines themselves, yet they get very sick: 21% of those hospitalized needed intensive care. Antibodies crossing the placenta may give them a head start. Protection was lower against Omicron (38%) than Delta (80%), and this 2021–2022 observational study predates updated shots.
See the evidence
A CDC-funded test-negative case-control study of 537 infants hospitalized with COVID and 512 hospitalized without it at 30 US hospitals, July 2021 to March 2022.
From the study: “The effectiveness of maternal vaccination against hospitalization for Covid-19 among infants was 52% (95% confidence interval [CI], 33 to 65) overall”
52% effective
Halasa NB et al. Maternal Vaccination and Risk of Hospitalization for Covid-19 among Infants. The New England journal of medicine. 2022.
Four years on, vaccinated adults aged 18 to 59 had fewer deaths.
25% lower death riskAll-cause deaths over 4 years, vaccinated vs unvaccinated adults aged 18 to 59
Among about 28 million French adults aged 18 to 59, those who got an mRNA vaccine in 2021 had a 25% lower risk of death from any cause over about 4 years than unvaccinated adults, after weighting for age, deprivation and 41 health conditions. Their risk of dying from severe COVID was 74% lower, and deaths from cancer, heart disease and injuries were lower too.
A common worry is that mRNA shots cause hidden deaths years later. In this national dataset covering all French adults aged 18 to 59, no rise appeared for any major cause of death. Observational study: people who chose vaccination may be healthier in ways not measured, so the 25% figure likely overstates benefit, though it argues against long-term harm.
See the evidence
A national cohort study using France's health insurance data, following about 28 million adults aged 18 to 59 from 2021 through March 2025.
From the study: “Vaccinated individuals had a 74% lower risk of death from severe COVID-19 (weighted hazard ratio [wHR], 0.26 [95% CI, 0.22-0.30]) and a 25% lower risk of all-cause mortality”
25% lower death risk
Semenzato L et al. COVID-19 mRNA Vaccination and 4-Year All-Cause Mortality Among Adults Aged 18 to 59 Years in France. JAMA network open. 2025.
From the study: “In this national cohort study of 28 million individuals, the results found no increased risk of 4-year all-cause mortality in individuals aged 18 to 59 years vaccinated against COVID-19”
25% lower death risk
Semenzato L et al. COVID-19 mRNA Vaccination and 4-Year All-Cause Mortality Among Adults Aged 18 to 59 Years in France. JAMA network open. 2025.
An estimated 232,000 US adult COVID deaths were preventable with vaccination.
232,000 deathsUS adult COVID deaths estimated preventable if unvaccinated adults had been vaccinated
Using CDC data from 30 US jurisdictions covering 68% of the population, researchers compared age-specific COVID death rates in vaccinated and unvaccinated adults. They estimated at least 232,000 deaths among unvaccinated adults from May 2021 to September 2022 could have been avoided with a primary series, 144,000 of them between May and early December 2021.
Vaccines were readily available to US adults by mid-2021, yet many stayed unvaccinated. Older adults bore most of this cost: 36.1% of the preventable deaths were in people aged 65 to 79. A rapid estimate that could not adjust for prior infection, health conditions or behavior differences between vaccinated and unvaccinated people, so the exact number is uncertain.
See the evidence
An analysis of CDC counts of laboratory-confirmed COVID deaths by vaccination status in 30 US jurisdictions, May 2021 to September 2022, scaled up to all US adults.
From the study: “We estimated that at least 232,000 deaths could have been prevented among unvaccinated adults during the 15 months had they been vaccinated with at least a primary series”
232,000 deaths
Jia KM et al. Estimated preventable COVID-19-associated deaths due to non-vaccination in the United States. European journal of epidemiology. 2023.
A nasal-spray COVID vaccine cut symptomatic infections 28.2%, missing its target.
28.2% efficacyProtection against symptomatic Omicron from two nasal-spray doses vs placebo
In a placebo-controlled trial in Colombia, the Philippines, South Africa and Viet Nam, two nasal-spray doses lowered symptomatic Omicron infections from 2.3% with placebo to 1.6% over a median of 161 days, an efficacy of 28.2%. That fell just short of the 30% success bar set in advance. Side effects, such as runny nose, were no more common than with placebo.
Nasal vaccines aim to build defenses where the virus enters, which could block infection and spread better than shots. This large trial of an early mucosal design shows modest protection so far. Tested in 2021–2022 in four countries outside the US; results apply to this one influenza-virus-based design, not to every nasal vaccine in development.
See the evidence
A randomized, double-blind, placebo-controlled phase 3 trial of adults at 33 centers in four countries, December 2021 to May 2022.
From the study: “was 1·6% in the vaccine group and 2·3% in the placebo group”
28.2% efficacy
Zhu F et al. Safety and efficacy of the intranasal spray SARS-CoV-2 vaccine dNS1-RBD: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet. Respiratory medicine. 2023.
From the study: “resulting in an overall vaccine efficacy of 28·2% (95% CI 3·4-46·6)”
28.2% efficacy
Zhu F et al. Safety and efficacy of the intranasal spray SARS-CoV-2 vaccine dNS1-RBD: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet. Respiratory medicine. 2023.
From the study: “The success criterion was predefined as vaccine efficacy of more than 30%.”
28.2% efficacy
Zhu F et al. Safety and efficacy of the intranasal spray SARS-CoV-2 vaccine dNS1-RBD: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet. Respiratory medicine. 2023.
Reinfection was less common with two vaccine doses than one
5.0% vs 7.7%
After 360 days, 5.0% of previously infected people with 2 vaccine doses had been reinfected, versus 7.7% with 1 dose.
Researchers compared matched groups, but the study cannot show cause. Testing may have missed reinfections without symptoms. With follow-up shorter than 24 days, the relative estimate’s uncertainty range included no difference.
Study details & original results
Chemaitelly, Hiam et al.. Two Versus One COVID-19 Vaccine Dose After Prior SARS-CoV-2 Infection: A Nationwide Retrospective Cohort Study.. Open forum infectious diseases. 2026.
Cumulative incidence of SARS-CoV-2 reinfection after 360 days among previously infected individuals receiving 2 vaccine doses versus 1 dose
Relative vaccine effectiveness of 2 doses versus 1 dose after prior SARS-CoV-2 infection within less than 24 days of follow-up; the confidence interval included no effectiveness.
Higher virus-blocking antibody levels after vaccination were linked to less severe illness
Higher levels of virus-blocking antibodies after vaccination were linked to less progression from infection to hospital or intensive-care admission.
Antibody levels and illness outcomes were measured in different studies. Other unmeasured differences could partly explain the link. A defined comparison group is not given here.
Study details & original results
Elias, Karen M et al.. Neutralising antibodies and protection from progression to severe COVID-19: A meta-analysis.. PLoS medicine. 2026.
Association between vaccine-induced neutralising antibody titres and progression from SARS-CoV-2 infection to severe COVID-19 (hospital or ICU admission); p<0.001. Neutralisation titres and clinical outcomes were measured in different studies, with possible unmeasured confounding.
RR 0.57 per 10-fold increase in GMT 95% CI: 0.51-0.64
Who gets vaccinated may affect hospitalization protection estimates
In Swedish adults aged 65 years or older, an estimate of protection against hospitalization may partly reflect healthier people receiving vaccination.
The study examined the 2024-2025 JN.1-adapted COVID-19 vaccine. The comparison group is not given here.
Study details & original results
Lyth, Johan et al.. Healthy vaccinee effect in the evaluation of updated COVID-19 vaccines in elderly populations.. Nature communications. 2026.
Reported observational effectiveness of the 2024-2025 JN.1-adapted COVID-19 vaccine against COVID-19-related hospitalization among Swedish adults aged 65 years or older; the study's negative-control results suggest this estimate may be affected by healthy-vaccinee selection.
Fully vaccinated prisoners had lower infection odds than unvaccinated prisoners
A review combining studies of risk factors found lower odds of COVID-19 infection in fully vaccinated prisoners than in unvaccinated prisoners.
The risk-factor analysis included 5 articles. The vaccine types, timing and actual infection risks are not given here. This compares odds in prisoners, not a change in the percentage infected.
Study details & original results
SeyedAlinaghi, SeyedAhmad et al.. Risk Factors of the Spread of COVID-19 in Prisoners: A Systematic Review and Meta-Analysis.. Disaster medicine and public health preparedness. 2026.
COVID-19 infection risk among fully vaccinated prisoners compared with unvaccinated prisoners; the risk-factor meta-analysis included 5 articles
Additional doses were linked to less need for hospital care for severe COVID-19
Among kidney transplant recipients, additional vaccine doses were linked to a lower chance of developing severe COVID-19 needing hospital care.
This Australian study group was studied during the Delta and Omicron BA.1/BA.2 waves. A named comparison group and follow-up length are not given here.
Study details & original results
Tharmaraj, Dhakshayini et al.. Critical role of vaccination in preventing severe coronavirus disease 2019: perspectives from clinical outcomes in an Australian kidney transplant recipient cohort.. Internal medicine journal. 2026.
Association of each additional vaccine dose with severe COVID-19 requiring hospitalization among kidney transplant recipients during the Delta and Omicron BA.1/BA.2 waves
aHR 0.50 per additional vaccine dose 95% CI: 0.40-0.65
A household study reported infections and a link with vaccination
The overall risk that household contacts would also be infected was 62.4%. Less household spread was reported when the household member identified as the primary case had been vaccinated within 6 months.
The vaccination comparison group is not given here. The overall contact estimate combines vaccination groups. Follow-up length is not given here.
Study details & original results
Benist, Sara C et al.. Recent COVID-19 Vaccination and Risk of SARS-CoV-2 Transmission.. JAMA network open. 2026.
Overall secondary infection risk among household contacts
62.4% 95% CI, 58.7%-65.5%
Reduced household transmission when primary case vaccinated ≤6 months prior
2025-2026 COVID-19 Vaccines had hospital and emergency-care estimates
Estimates for 2025-2026 COVID-19 Vaccines suggested fewer COVID-19 hospital admissions and emergency or urgent-care visits in adults.
The comparison group and follow-up period for 2025-2026 COVID-19 Vaccines are not given here. Results were also reported for adults aged 65 years or older.
Study details & original results
Wiegand, Ryan E et al.. Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design.. JAMA network open. 2026.
Vaccine effectiveness against COVID-19-associated hospitalization with 2025-2026 COVID-19 vaccine
55% 95% CI, 41%-66%
Vaccine effectiveness against COVID-19-associated ED/UC encounters with 2025-2026 COVID-19 vaccine
50% 95% CI, 42%-57%
Vaccine effectiveness against hospitalization in adults aged 65+ years
53% 95% CI, 37%-65%
Vaccine effectiveness against ED/UC encounters in adults aged 65+ years
The later hospital-protection estimate was less conclusive
The estimate suggested protection against JN.1 hospitalization at 2 to <30 weeks after vaccination. At 30 to <46 weeks, the uncertainty range included no difference.
This European study used a test-negative design, based on positive and negative tests. It examined BNT162b2 XBB:1.5-adapted vaccine during October 2023 to August 2024. The vaccination comparison group is not given here.
Study details & original results
Volkman, Hannah R et al.. Durability of the BNT162b2 XBB:1.5-adapted vaccine against JN.1 hospitalisation in Europe, October 2023 to August 2024: A test-negative case-control study using the id.DRIVE platform.. PloS one. 2026.
Vaccine effectiveness against JN.1-related hospitalization at 2 to <30 weeks since dose
64.5% 95% CI: 56.6; 71.0
Vaccine effectiveness against JN.1-related hospitalization at 30 to <46 weeks since dose
Dates show when findings were added here, not when papers were published. Study populations and comparisons differ.
WHEN YOU WANT TO GO DEEPERSee all 27 findingsOriginal results, comparisons and study details.
9 of 9 source groupsFindings stay together with their study.
SOURCE 205 findings
Chemaitelly, Hiam et al.. Two Versus One COVID-19 Vaccine Dose After Prior SARS-CoV-2 Infection: A Nationwide Retrospective Cohort Study.. Open forum infectious diseases. 2026.
Relative vaccine effectiveness of 2 doses versus 1 dose after prior SARS-CoV-2 infection within less than 24 days of follow-up; the confidence interval included no effectiveness.
Association between vaccine-induced neutralising antibody titres and progression from SARS-CoV-2 infection to severe COVID-19 (hospital or ICU admission); p<0.001. Neutralisation titres and clinical outcomes were measured in different studies, with possible unmeasured confounding.
Added
RR 0.57 per 10-fold increase in GMT95% CI: 0.51-0.64Source [17]
SOURCE 141 finding
Lyth, Johan et al.. Healthy vaccinee effect in the evaluation of updated COVID-19 vaccines in elderly populations.. Nature communications. 2026.
Reported observational effectiveness of the 2024-2025 JN.1-adapted COVID-19 vaccine against COVID-19-related hospitalization among Swedish adults aged 65 years or older; the study's negative-control results suggest this estimate may be affected by healthy-vaccinee selection.
SeyedAlinaghi, SeyedAhmad et al.. Risk Factors of the Spread of COVID-19 in Prisoners: A Systematic Review and Meta-Analysis.. Disaster medicine and public health preparedness. 2026.
Tharmaraj, Dhakshayini et al.. Critical role of vaccination in preventing severe coronavirus disease 2019: perspectives from clinical outcomes in an Australian kidney transplant recipient cohort.. Internal medicine journal. 2026.
Association of each additional vaccine dose with severe COVID-19 requiring hospitalization among kidney transplant recipients during the Delta and Omicron BA.1/BA.2 waves
Added
aHR 0.50 per additional vaccine dose95% CI: 0.40-0.65Source [12]
SOURCE 014 findings
Ma, Kevin C et al. Estimated Effectiveness of 2024-2025 COVID-19 Vaccination Against Severe COVID-19. JAMA Network Open. 2026.
Volkman, Hannah R et al.. Durability of the BNT162b2 XBB:1.5-adapted vaccine against JN.1 hospitalisation in Europe, October 2023 to August 2024: A test-negative case-control study using the id.DRIVE platform.. PloS one. 2026.
Wiegand, Ryan E et al.. Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design.. JAMA network open. 2026.
Volkman, Hannah R et al.. Durability of the BNT162b2 XBB:1.5-adapted vaccine against JN.1 hospitalisation in Europe, October 2023 to August 2024: A test-negative case-control study using the id.DRIVE platform.. PloS one. 2026.
Barboza, Ana Paula Bandeira et al.. Protective effect of a second booster dose against long COVID among individuals infected with SARS-CoV-2 in southeastern Brazil.. Vaccine. 2026.
Qian, Jiahui et al.. New-onset diabetes following SARS-CoV-2 infection in the Omicron era: a matched cohort study.. International journal of epidemiology. 2026.
Dobrescu, Andreea et al.. Effectiveness, Comparative Effectiveness, and Harms of COVID-19 Vaccines in Adults Who Are Not Pregnant or Immunocompromised: A Rapid Review for the American College of Physicians.. Annals of internal medicine. 2026.
Wiegand, Ryan E et al.. Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design.. JAMA network open. 2026.
Fitz-Patrick, David et al.. Immunogenicity, Tolerability, and Safety of BA.1-Adapted BNT162b2 Vaccine in 18- to 55-Year-Olds Previously Vaccinated with BNT162b2 or Who Were COVID-19 Vaccine-Naive.. Infectious diseases and therapy. 2026.
Blake, Alexandre et al.. Adapted XBB.1.5 vaccine effectiveness against severe COVID-19 outcomes among immunocompromised persons in 2023-24 in six European countries: a VEBIS-EHR network study.. Expert review of vaccines. 2026.
de Padua, Marina Coelho et al.. Effectiveness of BNT162B2 and CoronaVac vaccines in reducing COVID-19 severity among children aged 3-4 years in Brazil.. Vaccine. 2026.
Tharmaraj, Dhakshayini et al.. Critical role of vaccination in preventing severe coronavirus disease 2019: perspectives from clinical outcomes in an Australian kidney transplant recipient cohort.. Internal medicine journal. 2026.
SeyedAlinaghi, SeyedAhmad et al.. Risk Factors of the Spread of COVID-19 in Prisoners: A Systematic Review and Meta-Analysis.. Disaster medicine and public health preparedness. 2026.
Huiberts, Anne J et al.. Effectiveness of Omicron JN.1 vaccination against infection with JN.1-derived SARS-CoV-2 subvariants in a prospective cohort study in the Netherlands.. Vaccine. 2026.
Kazi, Fatema et al.. Implications for future pandemics from a living systematic review and critical evaluation of observational studies of the effectiveness of COVID-19 vaccination against the Omicron variant.. Vaccine. 2026.
Stadler, Eva et al.. COVID-19 vaccine effectiveness in people on immunosuppressive therapies: a systematic review and meta-analysis.. The Lancet. Microbe. 2026.
Yoon, Sarang K et al.. Real-world evaluation of 2023-2024 XBB.1.5 mRNA and protein-based COVID-19 vaccine reactogenicity from the randomized BEEHIVE trial.. Human vaccines & immunotherapeutics. 2026.
Chemaitelly, Hiam et al.. Two Versus One COVID-19 Vaccine Dose After Prior SARS-CoV-2 Infection: A Nationwide Retrospective Cohort Study.. Open forum infectious diseases. 2026.
Morris, Lisa et al.. Booster dose of COVID-19 vaccine and its effectiveness against post COVID-19 condition in individuals with pre-existing immunity: a sequential propensity score-matched cohort study.. EClinicalMedicine. 2026.
Yamamoto, Shohei et al.. Protection of Omicron XBB.1.5 vaccine, previous infection, and their induced neutralizing antibodies against symptomatic SARS-CoV-2 infection during Omicron KP.3 wave.. Vaccine. 2026.
Zhu F et al. Safety and efficacy of the intranasal spray SARS-CoV-2 vaccine dNS1-RBD: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet. Respiratory medicine. 2023.
Read each original paper for its complete methods, population and limitations. Different studies can ask different questions and report different kinds of results. Dates marked “added” describe when a finding entered this monitor, not when the study was published or clinically reviewed.
Download the findings and bibliography displayed in this page snapshot. Values and confidence intervals remain as reported text; this is not a pooled estimate or a systematic review. Product-label observations and editorial takeaways are excluded.
These findings may omit evidence or contain errors and have not been reviewed by a clinician. A citation or download does not establish source verification. Read the original studies for their methods and limitations.
The October 2026 COVID citation audit found errors in this collection. These downloads may still contain affected findings and bibliography entries. Read the correction record before using them.
“Added” dates record entry into the monitor, not publication or clinical review. A null original acquisition or derivation means its historical record is unknown; a current record or verification has its own observation time. The SHA-256 snapshot identifier binds the downloadable public fields. CSV includes finding rows and bibliography-only source rows; JSON includes both lists. Spreadsheet-sensitive CSV cells begin with an apostrophe for safety; JSON preserves the original text.
For attribution, cite ModernDoc and the page URL, data update date and snapshot identifier in the download. Original studies retain their own rights; this download does not grant a licence to their full text.