Yale School of Public Health - COVID-19 and Immune System Impacts

COVID-19 Vaccines Aren’t Causing AIDS

The truth behind a new preprint from a team at Yale

COVID-19 #CoronaVirus Infographic Datapack — Information is Beautiful

Updated daily, now with global vaccination stats

What Are COVID-19’s Long-Term Medical Effects?

Fascinating email from TPM Reader JO, whose personal bio is tailor-made for...

Underlying Conditions and the Higher Risk for Severe COVID-19

Learn risk factors for severe outcomes from COVID-19 and actions to take.

COVID-19 Vaccine Effectiveness and Safety for the 2026-2027 Respiratory Season

This Special Communication aims to identify and summarize the most recently published evidence evaluating the effectiveness and safety of US-licensed COVID-19 vaccines and report on the epidemiology of SARS-CoV-2 in the US.

COVID-19 Vaccine Effectiveness and Safety for the 2026-2027 Respiratory Season

Importance SARS-CoV-2 remains a substantial cause of respiratory illness, morbidity, and mortality. Evidence to date has demonstrated that COVID-19 vaccines reduce the risk of severe disease, including hospitalization and death. Objective This systematic review identifies and summarizes newly published studies reporting on the effectiveness and safety of COVID-19 vaccines and COVID-19 epidemiology in the US. Evidence Review Cochrane Central Register of Controlled Trials, PubMed/MEDLINE, Embase, and Scopus were searched from August 1, 2025, through June 29, 2026. Studies were eligible if they reported on the effectiveness, efficacy, or safety of a US-licensed COVID-19 vaccine or SARS-CoV-2 epidemiology in the US. Findings From 11 829 identified references, 155 publications were eligible (15 randomized clinical trials, 84 observational studies with a comparator group, 38 product safety studies without a comparator group [single group], and 18 descriptive studies of disease burden). Consistent with prior evidence, studies reported that updated COVID-19 vaccines were associated with a reduction in the risk of hospitalization among both older adults (≥65 years; vaccine effectiveness [VE], 53.0%; 95% CI, 37.0%-65.0%; 2025-2026 season) and adults (18-64 years; VE, 54.0%; 95% CI, 1.0%-78.0%; 2024-2025 season). Maternal vaccination was associated with reduced risk of COVID-19–associated emergency department/urgent care encounters among individuals vaccinated (VE, 58.0%; 95% CI, 24.0%-77.0%) and with fewer COVID-19–related hospital contacts in the first 2 months of life among infants born subsequently (VE range, 50.0%-54.0%), regardless of trimester of vaccination. Vaccination was also associated with a significant reduction in COVID-19–related pediatric emergency department visits (9 months to 4 years; VE, 76.0%; 95% CI, 58.0%-87.0%). Vaccination was associated with a reduced risk of critical COVID-19 illness (intensive care unit admission or death) in immunocompromised adults (VE range, 32.0%-53.0%, depending on condition and other factors). Health care personnel who received 3 to 5 vaccine doses were less likely to develop laboratory-confirmed COVID-19 illness (VE, 41.0%; 95% CI, 34.0%-47.0%) and postacute COVID-19 symptoms (VE, 57.0%; 95% CI, 46.0%-66.0%) compared with those who received only 2 doses. Across adverse events of special interest (eg, stroke, thrombosis, myocarditis), safety profiles were consistent with those of previous reviews. No identified studies conducted under the updated guidance on extended dosing intervals for the primary series reported an increased risk of myocarditis or pericarditis. No new safety signals were reported in the recently published studies eligible for this updated review of US-licensed COVID-19 vaccines. Conclusions and Relevance COVID-19 vaccines were consistently associated with a reduction in the risk of hospitalization and other outcomes, including among individuals at high risk of severe COVID-19, such as infants, and those who were pregnant. No new safety concerns were identified.

The Sick Times - Chronicling the Long COVID crisis

Chronicling the Long COVID crisis

Archive: New COVID-19 ‘Citizen Science’ Initiative Lets Any Adult with a Smartphone Help to Fight Coronavirus

The online study would try to help researchers gain insight into how the virus is spreading and identify ways to predict and reduce the number of new infections.

microCOVID/microCOVID

Estimating the COVID risk of ordinary activities

Opinion | When It Comes to Covid-19, Most of Us Have Risk Exactly Backward (Published 2020)

We aren’t very good at discussing trade-offs, but we need to make some during this pandemic.

Vascular and inflammatory diseases after COVID-19 infection and vaccination in children and young people in England: a retrospective, population-based cohort study using linked electronic health records

Children and young people have higher risks of rare vascular and inflammatory diseases up to 12 months after a first COVID-19 diagnosis and higher risk of rare myocarditis or pericarditis up to 4 weeks after a first BNT162b2 vaccine, although the risk following vaccination is substantially lower than the risk following infection. These findings are of great importance for national policy makers and caregivers considering vaccination consent for children, and support the public health strategy of COVID-19 vaccination in children and young people to mitigate the more frequent and persistent risks associated with SARS-CoV-2 infection.