BBIBP-CorV (Sinopharm) vaccination- induced immunity is affected by age, gender and prior COVID-19 and activates responses to spike and other antigens

Long-term solutions against SARS-CoV-2 infections require understanding of immune protection induced by different vaccine COVID-19 formulations. We investigated humoral and cellular immunity induced by Sinopharm (BBIBP-CorV) in a region of high SARS-CoV-2 seroprevalence. Levels of IgG antibodies to SARS-CoV-2 spike protein and its receptor-binding domain (RBD) were determined 24-weeks. Cellular immunity was investigated using a commercially available IFN-{gamma} release assay to SARS-CoV-2 spike (Ag1 and 2) and extended genome antigens (Ag3). Increasing IgG seropositivity to Spike protein and RBD was observed post-vaccination. Seropositivity was reduced in those over 50 years and raised in females and those with prior COVID-19. After 20 weeks post-vaccination, only one third of participants had positive T cell responses to SARS-CoV-2 antigens. Prior COVID-19 impacted IFN{gamma} responses, with reactivity enhanced in those infected earlier. The frequency of IFN{gamma} responses was highest to extended genome antigen set. Overall, BBIBP-CorV- induced antibody responses were impacted by age, gender and prior COVID-19. Cellular immunity was present in a limited number of individuals after 20 weeks but was enhanced by prior infection. This suggests the need for booster vaccinations in older individuals. BBIBP-CorV-induced cellular activation is broader than to spike, requiring further study to understand how to monitor vaccine effectiveness.

Balancing science and public policy in Pakistan’s COVID-19 response

Background: Coronavirus disease 2019 (COVID-19) has affected the world in an unprecedented manner and South Asian countries were among the first to experience imported cases. Pakistan’s response to COVID-19 has been under scrutiny for its granularity, reach and impact. Aims: to evaluate objectively the chronology and depth of the response to COVID-19 in Pakistan. Methods: We evaluated available national and subnational epidemiological and burden information on COVID-19 cases and deaths in Pakistan, including projection models available to the Government at an early stage of the pandemic. Results: Pakistan, with a population of 215 million and considerable geographic diversity, experienced case introduction from pilgrims returning from the Islamic Republic of Iran, followed by widespread community transmission. The National Command and Operations Centre, established through civilian and military partnership, was critical in fast tracking logistics, information gathering, real-time reporting and smart lockdowns, coupled with a massive cash support programme targeting the poorest sections of society. Cases peaked in June 2020 but the health system was able to cope with the excess workload. Since then, although testing rates remain low (> 300 000 cases confirmed to date), case fatality rates have stabilized, and with 6300 deaths, Pakistan seems to have flattened the COVID-19 curve. Conclusion: Despite notable successes in controlling the pandemic, several weaknesses remain and there are risks of rebound as the economy and educational systems reopen. There is continued need for strong technical and programmatic oversight, linked to civic society engagement and working with religious scholars to ensure nonpharmacological intervention compliance.

Evaluation of effects of public health interventions on COVID-19 transmission for Pakistan: A mathematical simulation study

BackgroundIn an effort to contain the COVID-19 epidemic, many governments across the world have enforced lockdown or social distancing measures. Several outbreak models have been developed to investigate the effects of different public health strategies for COVID-19, but they have not been developed for Pakistan and other South East Asian countries, where a large proportion of global population resides. MethodsWe developed a stochastic individual contact model by extending the widely-used Susceptible-Infectious-Recovered (SIR) compartment model with additional compartments to model both anticipated mitigating effects of public health intervention strategies for Pakistan. We estimated the projected spread, number of hospitalizations, and case fatalities under no intervention and four increasingly stringent public health strategies of social distancing and self-isolation at the national and provincial levels of Pakistan. ResultsOur analysis shows that without any public health interventions the expected number of cumulative case fatalities is 671,596 in Pakistan with the virus is expected to peak in terms of the number of required ICU-hospitalizations at 198,593 persons by the end of the June 2020. The estimated total numbers of cumulative case fatalities are lower for other public health strategies with strict social distancing showing the lowest number of deaths at 1,588 (Self-isolation: n=341,359; Flexible social distancing strategy: n=3,995; and Exit strategy: n=28,214). The lowest number of required ICU-hospitalization is also estimated for strict social distancing strategy (n=266 persons at the end of May 2020). Generally, the simulated effects of the different public health strategies at the provincial-level were similar to the national-level with strict social distancing showing the fewest number of case fatalities and ICU-hospitalizations. ConclusionOur results indicate that case fatalities and ICU-hospitalizations for Pakistan will be high without any public health interventions. While strict social distancing can potentially prevent a large number of deaths and ICU-hospitalizations, the government faces an important dilemma of potentially severe economic downfall. Consideration of a temporary strict social distancing strategy with gradual return of the lower-risk Pakistani population, as simulated in our exit strategy scenario, may an effective compromise between public health and economy of Pakistani population.