In vitro neutralizing activity of BNT162b2 mRNA-induced antibodies against full B.1.351 SARS-CoV-2 variant (preprint)

Background: SARS-CoV-2 variation represents a serious challenge to current COVID-19 vaccines. Recent reports suggest that B.1.351 and other variants may escape the neutralization activity of the antibodies generated by current vaccines. Methods: Ninety-nine healthcare workers undertaking BNT162b2 mRNA vaccination were sampled at baseline, on the day of the second dose, and 14 days after the latter. Neutralization activity against SARS-CoV-2 B.1, B.1.1.7 and B.1.351 was investigated using a Vero-E6 model. Results: Eleven of the study participants had prior infection with SARS-CoV-2. Neutralization titers against the B.1 and the B.1.1.7 variants were not statistically different and were significantly higher than titers against the B.1.351 variant across pre-exposed and non-pre-exposed vaccinated individuals ( p <0.01). While all vaccinated individuals presented neutralizing antibodies against B.1 and B 1.1.7 after the second dose, 14% were negative against B.1.351, and 76% had low titers (1/20-1/80). Pre-exposed vaccinated individuals showed higher titers than non-pre-exposed after the first (median titers of 1/387 versus 1/28, respectively) and the second doses (1/995 versus 1/703, respectively). As high as 72% of the pre-exposed vaccinees presented titers >1/80 after a single dose, while only 11% of non-exposed vaccinated individuals had titers >1/80. Conclusions: BNT162b2 mRNA-induced antibodies show a lower in vitro neutralizing activity against B.1.351 variant compared to neutralization against B.1.1.7 or B.1 variants. Interestingly, for individuals pre-exposed to SARS-CoV-2, one dose of BNT162b2 mRNA may be adequate to produce neutralizing antibodies against B.1.1.7 and B.1, while two doses of BNT162b2 mRNA provide optimal neutralizing antibody response against B.1.351 too.

In Vitro Neutralizing Activity of BNT162b2 mRNA-Induced Antibodies Against B.1.351 SARS-CoV-2 Variant in Pre-Exposed and Non-Pre-Exposed Vaccinees (preprint)

Background: SARS-CoV-2 variation represents a serious challenge to current COVID-19 vaccines. Recent reports suggest that B.1.351 and P1/P2 variants may escape the neutralization activity of the antibodies generated by BNT162b2 mRNA vaccine.Methods: Ninety-nine healthcare workers undertaking BNT162b2 mRNA vaccination were sampled at baseline, on the day of the second dose, and 14 days after the latter. Neutralization activity against SARS-CoV-2 B.1, B.1.1.7 and B.1.351 was investigated using a Vero-E6 model.Results: Eleven of the study participants had prior infection with SARS-CoV-2. Neutralization titers against the B.1 and the B.1.1.7 variants were not statistically different and were significantly higher than titers against the B.1.351 variant across pre-exposed and non-pre-exposed vaccinated individuals (p<0.01). While all vaccinated individuals presented neutralizing antibodies against B.1 and B 1.1.7 after the second dose, 14% were negative against B.1.351, and 76% had low titers (1/20-1/80). Pre-exposed vaccinated individuals showed higher titers than non-pre-exposed after the first (median titers of 1/387 versus 1/28, respectively) and the second doses (1/995 versus 1/703, respectively). As high as 72% of the pre-exposed vaccinees presented titers >1/80 after a single dose, while only 11% of non-exposed vaccinated individuals had titers >1/80.Conclusions: BNT162b2 mRNA-induced antibodies show a lower in vitro neutralizing activity against B.1.351 variant compared to neutralization against B.1.1.7 or B.1 variants. Interestingly, for individuals pre-exposed to SARS-CoV-2, one dose of BNT162b2 mRNA may be adequate to produce neutralizing antibodies against B.1.1.7 and B.1, while two doses of BNT162b2 mRNA provide optimal neutralizing antibody response against B.1.351 too.Funding Statement: None to declare.Declaration of Interests: None to declare.Ethics Approval Statement: The protocol was approved by the Ethics Committee of the Hospital Universitario Clínico San Cecilio (HUSC 0670-N-21). All participants provided informed consent.

Active tobacco smoking is associated with lower risk of acquiring SARS-CoV-2 infection among people living with HIV (preprint)

SummaryThe relationship between tobacco smoking and SARS-CoV-2 infection is poorly understood. We aimed to assess the impact of current smoking on the risk of COVID-19 acquisition in a well-controlled HIV-infected population. We found that, in this setting, tobacco smoking is associated with a lower risk of acquiring SARS-CoV-2 infection.

Incidence of COVID-19 among people living with HIV in Southern Spain (preprint)

Objective and Design: The incidence of SARS-CoV-2 infection among people living with HIV (PLWH) has been estimated on the basis of reported symptomatic clinical cases. However, as asymptomatic cases are common and there have been limitations of health care systems for COVID-19 microbiological diagnosis, these estimations may be misleading. The availability of reliable serology for the diagnosis of COVID-19 may overcome this drawback. This study was carried out in order to reveal the actual incidence of SARS-CoV-2 infection in PLWH in Southern Spain.Methods: This is a prospective cohort study including HIV infected patients from the Unit of Infectious Diseases of a university hospital in Seville, Southern Spain. Patients were enrolled in the study if 1) they had attended the outpatient clinic from September 1st to December 31st, 2019 (baseline), and 2) had a subsequent evaluation from March 1st to June 30th, 2020 (intra-pandemic). Serum antibodies against SARS-CoV-2 were determined in baseline and intra-pandemic samples.Results: 326 patients were included in the study. Of them, 4 (1.25% [95% CI: 0.3%-3.1%]) developed COVID-19. One patient developed bilateral pneumonia and died. The remaining three showed mild respiratory symptoms suggesting COVID-19. No asymptomatic SARS-CoV-2 infection was observed in this study. No patient with COVID-19 was tobacco smoker. The incidence of COVID-19 among non-smokers was 2.5% (95% CI [0.6%-6%], p=0.057 versus smokers).Conclusions: The incidence of COVID-19 among PLWH in our area was low and similar to that observed in the general population. The frequency of asymptomatic cases might be lower than in patients without HIV infection. Tobacco smoking could be associated to a lower incidence of COVID-19.

Sample Pooling as an efficient strategy for SARS-COV-2 RT-PCR screening: a multicenter study in Spain (preprint)

Importance: The actual demand on SARS-CoV-2 diagnosis is a current challenge for clinical laboratories. Sample pooling may help to ameliorate workload in clinical laboratories. Objective: to evaluate the efficacy of sample pooling compared to the individual analysis for the diagnosis of CoVID-19, by using different commercial platforms for nucleic acid extraction and amplification. Design and settings: observational, prospective, multicentre study across 9 Spanish clinical microbiology laboratories including SARS-CoV-2 RNA testing performed in April 2020, during the first three days after acceptance to participate. Participants and Methods: 3519 naso-oro-pharyngeal samples received at the participating laboratories were processed individually and in pools (351 pools) according to the existing methodology in each of the centres. Results: We found that 253 pools (2519 samples) were negative, and 99 pools (990 samples) were positive; with 241 positive samples (6.85%), our pooling strategy would have saved 2167 PCR tests. For 29 pools (made out of 290 samples) we found discordant results when compared to their correspondent individual samples: in 24/29 pools (30 samples), minor discordances were found; for five pools (5 samples), we found major discordances. Sensitivity, specificity, positive and negative predictive values for pooling were 97.93%, 100%, 100% and 99.85% respectively; accuracy was 99.86% and kappa concordant coefficient was 0.988. As a result of the sample dilution effect of pooling, a loss of 2-3 Cts was observed for E, N or RdRP genes. Conclusion: we show a high efficiency of pooling strategies for SARS-CoV-2 RNA testing, across different RNA extraction and amplification platforms, with excellent performance in terms of sensitivity, specificity, and positive and negative predictive values. We believe that our results may help clinical laboratories to respond to the actual demand and clinical need on SARS-CoV-2 testing, especially for the screening of low prevalence populations.