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Updated Evidence for Covid-19, RSV, and Influenza Vaccines for 2025–2026

Author/s: 
Michael S. Abers, Jake Scott, Harleen K. Marwah, Nicole C. McCann, Eric A. Meyerowitz, Aaron Richterman, Derek F. Fleming, Caitlin M. Dugdale

Background: Changes in the vaccine advisory process in the United States have disrupted immunization guidance, which reinforces the need for independent evidence review to inform decisions regarding immunization for respiratory viruses during the 2025-2026 season.

Methods: We conducted a systematic review of U.S.-licensed immunizations against coronavirus disease 2019 (Covid-19), respiratory syncytial virus (RSV), and influenza. We searched databases on PubMed/MEDLINE, Embase, and Web of Science for updates of the most recent review by the Advisory Committee on Immunization Practices (ACIP) Evidence-to-Recommendations for each disease, which was performed during the 2023-2024 period. Outcomes included vaccine efficacy and effectiveness against hospitalization, other clinical end points, and safety.

Results: Of 17,263 identified references, 511 studies met the inclusion criteria. Covid-19 mRNA vaccines against the XBB.1.5 subvariant had pooled vaccine effectiveness against hospitalization of 46% (95% confidence interval [CI], 34 to 55; from cohort studies) and 50% (95% CI, 43 to 57; from case-control studies) among adults and 37% (95% CI, 29 to 44) among immunocompromised adults. In a case-control study, vaccines against the KP.2 subvariant showed an effectiveness of 68% (95% CI, 42 to 82). Maternal RSV vaccination (for infant protection), nirsevimab for infants, and RSV vaccines in adults who were 60 years of age or older showed vaccine effectiveness of 68% or more against hospitalization. Influenza vaccination had a pooled vaccine effectiveness of 48% (95% CI, 39 to 55) in adults between the ages of 18 and 64 years and 67% (95% CI, 58 to 75) in children against hospitalization. Safety profiles were consistent with previous evaluations. The diagnosis of myocarditis associated with Covid-19 vaccines occurred at rates of 1.3 to 3.1 per 100,000 doses in male adolescents, with lower risk associated with longer dosing intervals. The RSVpreF vaccine was associated with 18.2 excess cases of Guillain-Barré syndrome per million doses in older adults; a significant association with preterm birth was not observed when the vaccine was administered at 32 to 36 weeks' gestation.

Conclusions: Ongoing peer-reviewed evidence supports the safety and effectiveness of immunizations against Covid-19, RSV, and influenza during the 2025-2026 season. (Funded by the Center for Infectious Disease Research and Policy and the Alumbra Innovations Foundation.).

Keywords 
COVID-19 vaccine COVID-19 'Vaccination vaccines

What Do I Need to Know About the Pneumococcal Pneumonia Vaccine?

Author/s: 
Jerard Z. Kneifati-Hayek, Michael A. Incze

What Is the Pneumococcal Pneumonia Vaccine?
The pneumococcal vaccine protects against infections from a type of bacteria called pneumococcus. Pneumococcus is a common cause of pneumonia (a lung infection), as well as other serious infections. The vaccine prepares your immune system to recognize and fight pneumococcal bacteria. The vaccine is usually given through an injection into the arm. Some versions can also be inhaled. The vaccines do not contain living or dead bacteria. The pneumococcal vaccine does not protect you from other lung infections like the flu (influenza), COVID-19, RSV (respiratory syncytial virus), or other kinds of bacteria that cause pneumonia. It is still important to get your flu shot every year and other vaccines your doctor recommends, even if you already got the pneumococcal vaccine.

What Are Benefits of Pneumococcal Pneumonia Vaccines?
The vaccine substantially lowers your risk of hospitalization or dying from serious pneumococcal infection. Vaccination can reduce the risk of pneumonia-related deaths by almost half.

Why Is There a New Pneumococcal Pneumonia Vaccine, and How Does It Differ From Prior Versions?
There are several types of pneumococcal bacteria that can cause pneumonia. Being vaccinated against one type of pneumococcus may not protect you from other types that could make you sick. Previous pneumococcal pneumonia vaccines like PPSV23 or PCV13 do not protect against all types of the pneumococcal bacteria that cause pneumonia. Newer vaccines were made in 2021 (PCV15 and PCV20) and 2024 (PCV21). These help to prevent infections from types of bacteria not covered by older versions.

What Are the Potential Side Effects?
Side effects are frequent but generally mild. The most common side effect is pain or redness at the site of injection. Less common side effects include fever, feeling tired, muscle ache, and headache. These are less severe than for other vaccines like flu and shingles. These effects can be treated with over-the-counter medications and generally go away within 24 to 48 hours. Life-threatening allergic reactions are extremely rare but possible. Seek immediate medical attention if you experience severe symptoms like difficulty breathing or progressive weakness after vaccination. The pneumonia vaccine cannot cause pneumonia or other bacterial illness.

Who Should Get a New Pneumococcal Pneumonia Vaccine?
All adults 50 years and older who have not been vaccinated should receive one of the new vaccines: PCV21, PCV20, or a sequence of PCV15 followed by PPSV23. People younger than 50 years with certain health problems should also get the new vaccine. These health problems include diabetes; chronic conditions affecting the heart, lungs, liver, or kidneys; current tobacco use or heavy alcohol consumption; a weak immune system from certain health problems or medications; absence or prior removal of the spleen; and a history of spinal fluid leak or a cochlear (inner ear) implant.

Most adults who got either PPSV23 and/or PCV13 should still get a booster with one of the newer vaccines. The different pneumococcal vaccines protect against different types of bacteria. Some types of bacteria are more common in people depending on their age, health, and where they live. Talk to your doctor about which vaccine is best for you.

Keywords 
'Vaccination Infectious diseases Patient Information Pneumococcal Vaccines

Evaluation of Waning of SARS-CoV-2 Vaccine–Induced Immunity

Author/s: 
Menegale, Francesco, Manica, Mattia, Zardini, Agnese, Guzzetta, Giorgio, Marziano, Valentina, d'Andrea, Valeria, Trentini, Filippo, Ajelli, Marco, Poletti, Piero, Merler, Stefano

Importance Estimates of the rate of waning of vaccine effectiveness (VE) against COVID-19 are key to assess population levels of protection and future needs for booster doses to face the resurgence of epidemic waves.

Objective To quantify the progressive waning of VE associated with the Delta and Omicron variants of SARS-CoV-2 by number of received doses.

Data Sources PubMed and Web of Science were searched from the databases’ inception to October 19, 2022, as well as reference lists of eligible articles. Preprints were included.

Study Selection Selected studies for this systematic review and meta-analysis were original articles reporting estimates of VE over time against laboratory-confirmed SARS-CoV-2 infection and symptomatic disease.

Data Extraction and Synthesis Estimates of VE at different time points from vaccination were retrieved from original studies. A secondary data analysis was performed to project VE at any time from last dose administration, improving the comparability across different studies and between the 2 considered variants. Pooled estimates were obtained from random-effects meta-analysis.

Main Outcomes and Measures Outcomes were VE against laboratory-confirmed Omicron or Delta infection and symptomatic disease and half-life and waning rate associated with vaccine-induced protection.

Results A total of 799 original articles and 149 reviews published in peer-reviewed journals and 35 preprints were identified. Of these, 40 studies were included in the analysis. Pooled estimates of VE of a primary vaccination cycle against laboratory-confirmed Omicron infection and symptomatic disease were both lower than 20% at 6 months from last dose administration. Booster doses restored VE to levels comparable to those acquired soon after the administration of the primary cycle. However, 9 months after booster administration, VE against Omicron was lower than 30% against laboratory-confirmed infection and symptomatic disease. The half-life of VE against symptomatic infection was estimated to be 87 days (95% CI, 67-129 days) for Omicron compared with 316 days (95% CI, 240-470 days) for Delta. Similar waning rates of VE were found for different age segments of the population.

Conclusions and Relevance These findings suggest that the effectiveness of COVID-19 vaccines against laboratory-confirmed Omicron or Delta infection and symptomatic disease rapidly wanes over time after the primary vaccination cycle and booster dose. These results can inform the design of appropriate targets and timing for future vaccination programs.

Keywords 
COVID-19 COVID-19 vaccine 'Vaccination

The monkeypox virus

Author/s: 
Halani, S., Mishra, S., Bogoch, I. I.

Monkeypox is a viral infection with person-to-person
transmission through direct contact or fomites
The virus is endemic to West and Central Africa.1
Animal-to-human transmission may initiate outbreaks, and person-to-person transmission
occurs through direct, close contact with a person during their infectious
stage through droplets, contact with infectious bodily fluids or via fomites
(e.g., linens). Airborne transmission is thought to be less common.

Keywords 
Monkeypox Virus Transmission Precautions 'Vaccination
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