Humoral and T-Cell Response before and after a Fourth BNT162b2 Vaccine Dose in Adults ≥60 Years.

Both humoral and cellular anamnestic responses are significant for protective immunity against SARS-CoV-2. In the current study, the responses in elderly people before and after a fourth vaccine dose of BNT162b2 were compared to those of individuals immunized with three vaccine doses. Although a boost effect was observed, the high response following the third administration questions the necessity of an early fourth boost.

Three-month follow-up of durability of response to the third dose of the SARS-CoV-2 BNT162b2 vaccine in adults aged 60 years and older: a prospective cohort study.

OBJECTIVE: To evaluate the durability of response 3 months after the third BNT162b2 vaccine in adults aged 60 years and older. DESIGN: Prospective cohort study. SETTING: Single tertiary centre. PARTICIPANTS: Healthcare workers/family members aged ≥60 years old who received the third BNT162b2 dose. INTERVENTIONS: Blood samples were drawn immediately before (T0), 10-19 days (T1) and 74-103 days (T2) after the third dose. PRIMARY AND SECONDARY OUTCOME MEASURES: Anti-spike IgG titres were determined using a commercial assay and seropositivity was defined as ≥50 arbitrary units (AU)/mL. Neutralising antibody titres were determined at T2. Adverse events, COVID-19 infections and Clinical Frailty Scale (CFS) levels were documented. RESULTS: The analysis included 97 participants (median age, 70 years (IQR, 66-74), 58% CFS level 2). IgG titres, which increased significantly from T0 to T1 (median, 440 AU/mL (IQR, 294-923) and median, 25 429 AU/mL (IQR, 14 203-36 114), respectively; p<0.001), decreased significantly by T2, but all remained seropositive (median, 8306 AU/mL (IQR, 4595-14 701), p<0.001 vs T1). In a multivariable analysis, only time from the second vaccine was significantly associated with lower IgG levels at T2 (p=0.017). At T2, 60 patients were evaluated for neutralising antibodies; all were seropositive (median, 1294 antibody titres; IQR, 848-2072). Neutralising antibody and anti-spike IgG levels were correlated (r=0.6, p<0.001). No major adverse events or COVID-19 infections were reported. CONCLUSIONS: Anti-spike IgG and neutralising antibody levels remain adequate 3 months after the third BNT162b2 vaccine in healthy adults aged ≥60 years, although the decline in IgG is concerning. A third dose of vaccine in this population should be top priority.

Characteristics of long-COVID among older adults: a cross-sectional study.

OBJECTIVES: To describe long-COVID symptoms among older adults and to assess the risk factors for two common long-COVID symptoms: fatigue and dyspnea. METHODS: This is a multicenter, prospective cohort study conducted in Israel, Switzerland, Spain, and Italy. Individuals were included at least 30 days after their COVID-19 diagnosis. We compared long-COVID symptoms between elderly (aged >65 years) and younger individuals (aged 18-65 years) and conducted univariate and multivariable analyses for the predictors of long-COVID fatigue and dyspnea. RESULTS: A total of 2333 individuals were evaluated at an average of 5 months (146 days [95% confidence interval 142-150]) after COVID-19 onset. The mean age was 51 years, and 20.5% were aged >65 years. Older adults were more likely to be symptomatic, with the most common symptoms being fatigue (38%) and dyspnea (30%); they were more likely to complain of cough and arthralgia and have abnormal chest imaging and pulmonary function tests. Independent risk factors for long-COVID fatigue and dyspnea included female gender, obesity, and closer proximity to COVID-19 diagnosis; older age was not an independent predictor. CONCLUSION: Older individuals with long-COVID have different persisting symptoms, with more pronounced pulmonary impairment. Women and individuals with obesity are at risk. Further research is warranted to investigate the natural history of long-COVID among the elderly population and to assess possible interventions aimed at promoting rehabilitation and well-being.

Using external data to assess the external validity of a randomised controlled trial.

BACKGROUND: Few studies have addressed external validity of randomized controlled trials in infectious diseases. We aimed to assess the external validity of an investigator-initiated trial on treatment for uncomplicated urinary tract infection. METHODS: In the original study, women (n = 513) with urinary tract infection were randomized to nitrofurantoin or fosfomycin treatment in three countries between 2013 and 2017. In the present study we compared women who were screened for enrolment but excluded to women who participated in the trial, both groups in Israel. The primary outcome was the rate of emergency department index visits resulting in hospitalization within 28 days. RESULTS: We compared 127 included to 110 excluded patients. The most common reasons for exclusion were logistic difficulties in recruitment and antibiotic use in the preceding month. Included patients tended to be older [39 (IQR 29-59) vs. 35.5 (IQR 24-56.25 years)], more likely to have history of recurrent infection and had more urinary symptoms. Among excluded patients, 13.6% (15/110) had initial visits resulting in hospitalization compared to 3.1% (4/127) of included participants (p = .003). The rate of emergency department visits within 28 days was similar in both groups. Clinical and microbiological failures were significantly more common in included patients [26% (33/127) vs. 1.8% (2/110), p < .001; 7.9% (10/127) vs. 0% (0/110), p = .003; respectively]. CONCLUSIONS: While differences were observed between included and excluded patients, the excluded group did not represent a more 'complicated' population. The present study shows the importance of collecting data on patients excluded from randomized controlled trials.