SARS-CoV-2: big seroprevalence data from Pakistan-is herd immunity at hand?

PURPOSE: Seroprevalence surveys from different countries have reported SARS CoV-2 antibodies below 20% even in the most adversely affected areas and herd immunity cannot be predicted till more than half of the population gets the disease. The purpose of this survey was to estimate the magnitude of community-based spread of the infection, associated immunity, and the future prospects and proximity to a 'herd community'. METHODS: The study was undertaken as a cluster randomized, cross-sectional countrywide survey. This largest community-based seroprevalence data of SARS-CoV-2 were collected between 15th and 31st July, 2020 from seven randomly selected cities belonging to the three most populous provinces of Pakistan. The FDA approved kit of ROCHE was used for detection of SARS-CoV-2 antibodies. RESULTS: Serum samples of 15,390 participants were tested for SARS CoV-2 antibodies with an overall seroprevalence of 42.4%. The seroprevalence ranged from 31.1% to 48.1% in different cities with the highest in Punjab province (44.5%). In univariable analysis, the odds of seropositivity was higher in men compared to women (OR: 1.10, 95% CI: 1.01-1.19, P < 0.05). In multivariable analysis, the risk of being seropositive was lower (OR 0.72, 95% CI: 0.60-0.87, P < 0.01) in younger group (≤ 20 years) than in those aged above 60 years. CONCLUSION: The study concluded that despite a reasonable seroprevalence, the country is yet to reach the base minimum of estimations for herd immunity. The durability of immunity though debated at the moment, has shown an evidenced informed shift towards longer side.

Anti-nucleocapsid IgG antibodies in SARS-CoV-2 recovered health care workers: One year follow-up study.

Objective: The objective of this study was to evaluate the magnitude and durability of the anti-nucleocapsid-IgG antibody titer in healthcare workers previously infected with SARS-CoV-2 for a period of 12 months.Methods: This study examined blood samples for SARS-CoV-2-specific IgG collected periodically from 120 healthcare workers previously infected with SARS-CoV-2 (confirmed by RT-PCR) and followed longitudinally up to 12 months from their enrolment into the study.Results: The median anti-N-IgG antibody level identified at 3 months was 23.7 CO-index (IQR: 9.13-50.27) and increased to 32.9 CO-index (IQR: 11.8-84.4) at 6 months. At 9 months, the median anti-N-IgG antibody level started to wane in the subsequent time and was dropped to 14 CO-index (IQR: 3.4-37.6) and declined further to 9.8 CO-index at 12 months (IQR: 2.8-9.8). When classified by age groups, the only statistically significant difference in anti-N-IgG between the two age groups (≤30 years and >30 years) was identified at 12 month time point (median difference 8.06, p = 0.035). Spearman correlation coefficient was negatively associated between anti-N-IgG and time interval (r = -0.255, p = 0.000) but was not statistically significant with age of a patient (p > 0.05).Conclusions: In conclusion, SARS-CoV-2 antibody levels started declining after 6 months but remained detectable in the majority of patients up to 12 months.

Predictive Potential Of Il28b Gene In Hcv Patients, Resistant To Daclatasvir And Sofosbuvir In KPK Population.

Background: Recently various combinations of direct acting antivirals (DAAs) have been tried successfully. The Sofosbuvir + Daclatasvir combination has been used with promising results. Recently, resistance has been noticed against DAAs. Therefore, polymorphism at particular sites in the interleukin 28B gene are under study to find possible association with resistance. This study was aimed at finding out any association of SNPs rs8099917 and rs12979860 (IL28B gene) with response and resistance to treatment in HCV genotype 3 patients in Khyber Pakhtunkhwa. Methods: This cross sectional, Analytical study was conducted at Gastroenterology/hepatology OPD of Prime Teaching Hospital, Peshawar Medical College. Collected Samples were stored at -20o C in PCR Lab of the College. DNA extraction and genotyping was carried out at BJ Molecular Biology Lab in Rawalpindi. Data was analyzed by using SPSS version 21. Chi-Square Test was used to see the statistically significant differences between rs8099917 T/G and rs12979860 T/C model. Results: In the IL28-B gene, single nucleotide polymorphism at rs12979860 T/C model, we observed that there are 37.5% CC homozygous, 12.5% TT homozygous and 50% CT heterozygous genotypes in resistant patients and 42.85% CC homozygous, 28.57% TT and 28.57% CT genotype in responder group. In rs12979860 T/C model, genotype of IL28-B in the responder and resistant group significantly varies at p-value =0.00572. Conclusion: We conclude that in SNP at rs12979860, CC genotype is associated with clearance of HCV, while CT genotype was more prevalent in the resistant group and associated with chronicity.

Identifying higher risk subgroups of health care workers for priority vaccination against COVID-19.

Background: Health care workers (HCWs) are exposed to high risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection due to close contact with infected patients in hospital. The objective of this study was to estimate the seroprevalence and to identify the exposure risk of various subgroups among HCWs to prioritize them for early vaccination. Methods: This was a multicentre cross-sectional study conducted between 15 and 29 June 2020. A total of 987 HCWs were recruited randomly from two major tertiary-care hospitals of Peshawar city, Pakistan. The HCWs included doctors, nurses, paramedics and hospital support staff. The US Food and Drug Administration (FDA)-approved kit was used for the detection of SARS-CoV-2 antibodies. Results: Overall, 310 (31.4%) HCWs were seropositive for SARS-CoV-2 antibodies (95% confidence interval, CI: 28.5-34.4). Seroprevalence was higher in males (33.5%) and in age group 51-60 years (40.9%). Seropositivity increased with increasing age from 8.3% in age group ⩽20 to 40.9% in 51-60 years of age group (p < 0.05). The highest seroprevalence was identified in paramedical staff (42·5%, 95% CI: 36.6-48.6) followed by nursing staff (38·8%, 95% CI: 32.1-45.7). In logistic regression, being a male HCW led to higher risk of seropositivity (odds ratio, OR: 1.50, 95% CI: 1·06-2.13. p < 0.05) compared with female staff members. The odds of seropositivity was higher in nurses (OR: 3·47, 95% CI: 1.99-6.05. p < 0.01), paramedical staff (OR: 3·19, 95% CI: 1.93-5.28. p < 0.01) and hospital support staff (OR: 2·47, 95% CI: 1.29-4.7. p < 0.01) compared with consultants. Conclusion: Overall, our results concluded that nursing and paramedical staff are at higher risk and should be vaccinated on priority.

Role of interferon anti body in predicting the response to interferon therapy in HCV patients.

OBJECTIVE: To see the frequency of formation of interferon antibodies in patients receiving alpha interferon and evaluate their role in treatment response. METHODS: Patients with chronic Hepatitis C receiving alpha interferon three times a week along with daily ribavarin in two gastroeneterolgy departments of public hospitals, running hepatology clinics were studied. Blood for interferon antibodies in most (71) cases was collected around 5th month of therapy, sera were stored and analyzed in batches. Sera of 134 patients was analyzed, of whom 44 were taking Interferon 2a and 90 were taking 2b. RESULTS: Of 134 cases, 17 showed the presence of antibodies in titers of over 50 units and 5 of these showed no response to interferon treatment (6%). Majority (78) of the cases had antibody levels of less than 20 followed by 39 cases whose levels ranged between 20-50 units. CONCLUSIONS: Interferon antibodies are formed in a small percentage of cases receiving interferon and that too are in such low titers that they are not hampering the treatment. Serial antibody levels may be done to see if they remain stationary or increase with the continuation of the therapy.