Kinetics of Covid-19 antibodies in terms of titre and duration among healthcare workers: A longitudinal study

BACKGROUND Most individuals with Covid-19 infection develop antibodies specific to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the dynamics of these antibodies is variable and not well-studied. We aimed to determine the titres of naturally acquired antibodies over a 12-week follow-up. METHODS We recruited healthcare workers who had tested positive on a specific quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for SARS-CoV-2, and then tested for the presence of immunoglobulin G (IgG) antibody against the same virus at baseline and again at 6 and 12 weeks. The antibody titre was determined by a semi-quantitative assay based on signal/cut-off ratio. Healthcare workers with antibody positivity were divided into those with high titre (ratio ?12) and low titre (<12). Their demographic details and risk factors were surveyed through a Google form and analysed in relation to the antibody titres at three time-points. RESULTS Of the 286 healthcare workers, 10.48% had high antibody titres. Healthcare workers who had tested positive by qRT-PCR and those who had received the Bacille Calmette–Guérin (BCG) vaccination or other immune-boosters had a higher frequency of high antibody titres. While there was a significant decline in antibody titres at 6 and 12 weeks, 87.46% of individuals positive for IgG antibody persisted to have the antibody even at 12 weeks. CONCLUSION Healthcare workers who tested positive for SARS-CoV-2 on qRT-PCR had a high positivity for the specific antibody, which continued to express in them even at 12 weeks. Further follow-up is likely to enhance our understanding of antibody kinetics following SARS-CoV-2 infection.

Helicobacter pylori negative, non-steroidal anti-inflammatory drug-negative peptic ulcers in India.

Introduction The past decade has witnessed a global rise in the prevalence of peptic ulcer disease which is unrelated to non-steroidal anti-inflammatory drugs (NSAIDs) or Helicobacter pylori infection. Although initially recognized in the West, this disease is being increasingly recognized in the Asian population. The higher risk of bleeding and ulcer recurrence in this subgroup of patients highlights the clinical importance of analyzing the changing trends of peptic ulcer disease in developing countries. Aims To assess the proportion of non-NSAID, non-H. pylori peptic ulcer disease in an Indian cohort of patients with peptic ulcer disease managed at a tertiary care center; and to compare the gastric and duodenal ulcer subgroups in these patients. Methods Patients diagnosed with peptic ulcer disease were screened for a history of NSAID use and those with a negative history were tested for H. pylori using a combination of rapid urease test (RUT) and 14C-urea breath test (UBT). Only those cases which tested negative for both the tests were considered ‘H. pylori-negative’. Serum gastrin was measured in all patients included in the study. Results Seventy-four gastric ulcer (GU) and 54 duodenal ulcer (DU) patients with no history of NSAID use were enrolled. Of these, 36 GU (45.9%) and 16 DU (29.6%) patients were H. pylori-negative. The proportion of non- NSAID non-H. pylori gastric ulcers was significantly higher than duodenal ulcers (p<0.05). However, patients who tested negative for H. pylori did not differ significantly from those who tested positive with regard to age, gender, serum gastrin level, and presence of risk factors, like smoking and alcoholism. Conclusion The current study indicates existence of high proportion of non-NSAID, non-H. pylori peptic ulcer disease in Indian patients.