Waning immunity against respiratory syncytial virus during the COVID-19 pandemic.

Health jurisdictions have seen a near-disappearance of Respiratory Syncytial Virus (RSV) during the first year of the COVID-19 pandemic. Over a corresponding period, we report a reduction in RSV antibody levels and neutralization in women and infants one year into the COVID-19 pandemic (February - June 2021) compared to earlier in the pandemic (May - June 2020), in British Columbia (BC), Canada. This supports that humoral immunity against RSV is relatively short-lived and its establishment in infants requires repeated viral exposure. Waned immunity in young children may explain the inter-seasonal resurgence of RSV cases in BC as seen also in other countries.

Vaccination in Pregnancy against Pertussis: A Consensus Statement on Behalf of the Global Pertussis Initiative.

Infants are at high risk for severe morbidity and mortality from pertussis disease during early infancy. Vaccination against pertussis in pregnancy has emerged as the ideal strategy to protect infants during these early, vulnerable, first months of life. On 30 November and 1 December 2021, the Global Pertussis Initiative held a meeting that aimed to discuss and review the most up-to-date scientific literature supporting vaccination against pertussis in pregnancy and outstanding scientific questions. Herein, we review the current and historically published literature and summarize the findings as consensus statements on vaccination against pertussis in pregnancy on behalf of the Global Pertussis Initiative.

Decay of anti-Bordetella pertussis antibodies in women of childbearing age following COVID-19 non-pharmaceutical measures.

BACKGROUND: Immunization against Bordetella pertussis during pregnancy reduces morbidity from severe pertussis in young infants via trans-placental transfer of anti-B. pertussis Immunoglobulin G (IgG). Studies have reported a near disappearance of respiratory pathogens including B. pertussis following implementation of mitigation strategies to control Coronavirus disease 2019 (COVID-19). We explored how immunity against B. pertussis changed in women of childbearing-age through the COVID-19 pandemic. METHODS: Paired blood samples from females of childbearing-age collected at the beginning (May-June 2020) and nearly one year into the COVID-19 pandemic (February-May 2021) in British Columbia (BC), Canada were tested for anti-B. pertussis IgG levels. To ascertain whether early-pandemic IgG levels in 2020 reflected levels in pregnant women early in gestation, 1st trimester sera collected from age-matched healthy pregnant women in 2018 and 2019 were tested for anti-B. pertussis IgG. Levels were compared by t tests. P-value of 0.05 was assigned and statistical significance was set as p < 0.016 using Bonferroni correction. RESULTS: Annual provincial B. pertussis incidences per 100,000 in BC in 2020 (3/100,000) and 2021 (<1/100,000) approximated the lowest levels since 1990. In 2021 vs. 2020, anti-pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN) IgG levels declined in women of childbearing-age: 6.8 IU/ml (95 %CI, 4.2-10.9) vs. 8.4 IU/ml (5.1-13.9; p = 0.004); 18.8 IU/ml (10.9-32.2) vs. 23.6 IU/ml (13.2-42.1; p < 0.001); and 37.1 IU/ml (18.1-75.9) vs. 47.2 IU/ml (24.8-89.9; p = 0.092), respectively. Although all values were slightly higher, anti-PT, FHA and PRN IgG levels in women of childbearing age did not significantly differ in 2020 compared with early-gestation pregnant women in 2018-2019, 8.4 IU/ml (95% CI, 5.1-13.9) vs. 5.4 IU/ml (95% CI, 3.8-7.7; p = 0.166), 23.6 IU/ml (95% CI, 13.2-42.1) vs. 20.1 IU/ml (95% CI, 13.4-30.2; p = 0.656), and 47.2 IU/ml (24.8-89.9) vs. 17.3 IU/ml (95% CI, 10.5-28.7; p = 0.021), respectively. DISCUSSION: B. pertussis infections should be closely monitored during the relaxing of mitigation measures for COVID-19.

Global Perspectives on Immunization Against SARS-CoV-2 During Pregnancy and Priorities for Future Research: An International Consensus Paper From the World Association of Infectious Diseases and Immunological Disorders.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pregnancy is associated with a higher risk for severe morbidity and mortality when compared with infection in non-pregnant women of childbearing age. An increasing number of countries recommend immunization against SARS-CoV-2 in pregnant women. Recent studies provide preliminary and supportive evidence on safety, immunogenicity and effectiveness of coronavirus disease 2019 (COVID-19) vaccines in pregnant women; however, important knowledge gaps remain which warrant further studies. This collaborative consensus paper provides a review of the current literature on COVID-19 vaccines in pregnant women, identifies knowledge gaps and outlines priorities for future research to optimize protection against SARS-CoV-2 in the pregnant women and their infants.

Vaccination of Pregnant Women Against COVID-19.

Pregnant women are at increased risk for severe morbidity and mortality following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leading some countries to recommend vaccination of pregnant women against coronavirus disease 2019 (COVID-19). These recommendations are based on studies conducted early in the pandemic, and thus, the pregnant women in these studies most likely did not have pre-existing immunity to SARS-CoV-2 at the time of infection. The susceptibility of pregnant women and their infants to SARS-CoV-2 and the severity of infection may be attenuated as the pandemic progresses and an increasing number of women will have pre-existing immunity (following natural infection or vaccination prior to pregnancy) during pregnancy. The reactogenicity, immunogenicity and efficacy of COVID-19 vaccines administered in pregnancy may also be affected by the pre-existing immunity of pregnant women. Maternal vaccine trials should be evaluated in the context of their timing in the pandemic and interpreted based on the pre-existing immunity of pregnant women.

Coronavirus Disease-19: An Interim Evidence Synthesis of the World Association for Infectious Diseases and Immunological Disorders (Waidid).

Coronavirus disease 2019 (COVID-19) is a rapidly evolving, highly transmissible, and potentially lethal pandemic caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As of June 11 2020, more than 7,000,000 COVID-19 cases have been reported worldwide, and more than 400,000 patients have died, affecting at least 188 countries. While literature on the disease is rapidly accumulating, an integrated, multinational perspective on clinical manifestations, immunological effects, diagnosis, prevention, and treatment of COVID-19 can be of global benefit. We aimed to synthesize the most relevant literature and experiences in different parts of the world through our global consortium of experts to provide a consensus-based document at this early stage of the pandemic.

Importance of COVID-19 vaccine efficacy in older age groups.

IMPORTANCE: An effective vaccine against SARS-CoV-2 will reduce morbidity and mortality and allow substantial relaxation of physical distancing policies. However, the ability of a vaccine to prevent infection or disease depends critically on protecting older individuals, who are at highest risk of severe disease. OBJECTIVE: We quantitatively estimated the relative benefits of COVID-19 vaccines, in terms of preventing infection and death, with a particular focus on effectiveness in elderly people. DESIGN: We applied compartmental mathematical modelling to determine the relative effects of vaccines that block infection and onward transmission, and those that prevent severe disease. We assumed that vaccines showing high efficacy in adults would be deployed, and examined the effects of lower vaccine efficacy among the elderly population. SETTING AND PARTICIPANTS: Our mathematical model was calibrated to simulate the course of an epidemic among the entire population of British Columbia, Canada. Within our model, the population was structured by age and levels of contact. MAIN OUTCOME(S) AND MEASURE(S): We assessed the effectiveness of possible vaccines in terms of the predicted number of infections within the entire population, and deaths among people aged 65 years and over. RESULTS: In order to reduce the overall rate of infections in the population, high rates of deployment to all age groups will be critical. However, to substantially reduce mortality among people aged 65 years and over, a vaccine must directly protect a high proportion of people in that group. CONCLUSIONS AND RELEVANCE: Effective vaccines deployed to a large fraction of the population are projected to substantially reduce infection in an otherwise susceptible population. However, even if transmission were blocked highly effectively by vaccination of children and younger adults, overall mortality would not be substantially reduced unless the vaccine is also directly protective in elderly people. We strongly recommend: (i) the inclusion of people aged 65 years and over in future trials of COVID-19 vaccine candidates; (ii) careful monitoring of vaccine efficacy in older age groups following vaccination.