RESUMO
Vaccination is considered the most important measure to control the COVID-19 pandemic. Extensive follow-up studies with distinct vaccines and populations are able to promote robust and reliable data to better understand the effectiveness of this pharmacologic strategy. In this sense, we present data regarding binding and neutralizing (achieved by surrogate ELISA assay) antibodies throughout time, from vaccinated and previously infected (PI) health care workers (HCW) in Portugal. We analyzed serum samples of 132 HCW, who were vaccinated and with previous SARS-CoV-2 infection. Samples were collected before vaccination (baseline, M1), at second dose vaccine uptake (M2), and 25-70 days (M3) and 150-210 days (M4) after the second dose for vaccinated individuals. The IgG (anti-RBD/S) antibody geometric mean titers found on vaccinated HCW at M2 (GM = 116.1 BAU/mL; CI: 92.3-146.1) were significantly higher than those found on PI HCW at recruitment (M1) (GM = 35.9 BAU/mL; CI:15.4-83.4), and the neutralizing antibodies (nAb) were similar between these groups, of 93.2 UI/mL (95% CI 73.2-118.5) vs. 84.1 UI/mL (95% CI 40.4-155.9), respectively. We detected around 10-fold higher IgG (anti-RBD/S) antibodies titers in M3 when compared with M2, with a slight but significant decrease in titers from 36 days after the second dose vaccine uptake. The increase of nAb titers was correlated with IgG (anti-RBD/S) antibodies titers; however, in contrast to IgG (anti-RBD/S) antibodies titers, we did not detect a decrease in the nAb titer 36 days after a second vaccine dose uptake. At M4, a decrease of 8-fold in binding IgG (anti-RBD/S) and nAb was observed. No significant differences in antibody titers were observed by sex, age or chronic diseases. Our results suggest that IgG (anti-RBD/S) antibodies titers and nAb titers could be correlated, but an ongoing follow up of the cohort is required to better understand this correlation, and the duration of the immune response.
RESUMO
Early diagnosis and treatment are critical to minimize the spread and to reduce morbidity and mortality from tuberculosis. Clinical diagnosis is most time difficult resulting from non-specific and frequently indolent symptoms. Radiological presentation may be very diverse. Currently TB diagnosis still depends on microbiological exams which require a very careful and quick specimen handling. A positive acid-fast bacilli smear makes a rapid presumptive diagnosis. Nevertheless the gold-standard for diagnosis still is cultural-isolation of the Mycobacterium tuberculosis, which may take several weeks to attain. Biochemical (adenosine deaminase) and molecular techniques (nucleic acid amplification tests) are already approved for tuberculosis diagnosis and can provide rapid diagnostic information to the clinician. Numerous alternative diagnostic methods are still under experimentation but none of them has a recognized role. In most cases diagnosis of tuberculosis lays on an adequate combination of different diagnostic methods which is time-consuming. Even though in some cases laboratory confirmation is never obtained and diagnosis and treatment is established on suspicious basis. The purpose of this paper is to discuss the utility of the several diagnostic methods currently available and to point out most common difficulties found by the clinicians to the correct and timely diagnosis.
