Showing papers by "Pan American Health Organization published in 2021"

Effectiveness of the CoronaVac vaccine in older adults during a gamma variant associated epidemic of covid-19 in Brazil: test negative case-control study.

Abstract: Objective To estimate the effectiveness of the inactivated whole virus vaccine, CoronaVac (Sinovac Biotech), against symptomatic covid-19 in the elderly population of Sao Paulo state, Brazil during widespread circulation of the gamma variant. Design Test negative case-control study. Setting Community testing for covid-19 in Sao Paulo state, Brazil. Participants 43 774 adults aged ≥70 years who were residents of Sao Paulo state and underwent reverse transcription polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 from 17 January to 29 April 2021. 26 433 cases with symptomatic covid-19 and 17 622 test negative controls with covid-19 symptoms were formed into 13 283 matched sets, one case with to up to five controls, according to age, sex, self-reported race, municipality of residence, previous covid-19 status, and date of RT-PCR test (±3 days). Intervention Vaccination with a two dose regimen of CoronaVac. Main outcome measures RT-PCR confirmed symptomatic covid-19 and associated hospital admissions and deaths. Results Adjusted vaccine effectiveness against symptomatic covid-19 was 24.7% (95% confidence interval 14.7% to 33.4%) at 0-13 days and 46.8% (38.7% to 53.8%) at ≥14 days after the second dose. Adjusted vaccine effectiveness against hospital admissions was 55.5% (46.5% to 62.9%) and against deaths was 61.2% (48.9% to 70.5%) at ≥14 days after the second dose. Vaccine effectiveness ≥14 days after the second dose was highest for the youngest age group (70-74 years)—59.0% (43.7% to 70.2%) against symptomatic disease, 77.6% (62.5% to 86.7%) against hospital admissions, and 83.9% (59.2% to 93.7%) against deaths—and declined with increasing age. Conclusions Vaccination with CoronaVac was associated with a reduction in symptomatic covid-19, hospital admissions, and deaths in adults aged ≥70 years in a setting with extensive transmission of the gamma variant. Vaccine protection was, however, low until completion of the two dose regimen, and vaccine effectiveness was observe to decline with increasing age among this elderly population.

Effectiveness of CoronaVac among healthcare workers in the setting of high SARS-CoV-2 Gamma variant transmission in Manaus, Brazil: A test-negative case-control study.

Abstract: Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, Gamma, emerged in the city of Manaus in late 2020 during a large resurgence of coronavirus disease (COVID-19), and has spread throughout Brazil. The effectiveness of vaccines in settings with widespread Gamma variant transmission has not been reported. Methods We performed a matched test-negative case-control study to estimate the effectiveness of an inactivated vaccine, CoronaVac, in healthcare workers (HCWs) in Manaus, where the Gamma variant accounted for 86% of genotyped SARS-CoV-2 samples at the peak of its epidemic. We performed an early analysis of effectiveness following administration of at least one vaccine dose and an analysis of effectiveness of the two-dose schedule. The primary outcome was symptomatic SARS-CoV-2 infection. Findings For the early at-least-one-dose and two-dose analyses the study population was, respectively, 53,176 and 53,153 HCWs residing in Manaus and aged 18 years or older, with complete information on age, residence, and vaccination status. Among 53,153 HCWs eligible for the two-dose analysis, 47,170 (89%) received at least one dose of CoronaVac and 2,656 individuals (5%) underwent RT-PCR testing from 19 January, 2021 to 13 April, 2021. Of 3,195 RT-PCR tests, 885 (28%) were positive. 393 and 418 case-control pairs were selected for the early and two-dose analyses, respectively, matched on calendar time, age, and neighbourhood. Among those who had received both vaccine doses before the RT-PCR sample collection date, the average time from second dose to sample collection date was 14 days (IQR 7-24). In the early analysis, vaccination with at least one dose was associated with a 0.50-fold reduction (adjusted vaccine effectiveness (VE), 49.6%, 95% CI 11.3 to 71.4) in the odds of symptomatic SARS-CoV-2 infection during the period 14 days or more after receiving the first dose. However, we estimated low effectiveness (adjusted VE 36.8%, 95% CI -54.9 to 74.2) of the two-dose schedule against symptomatic SARS-CoV-2 infection during the period 14 days or more after receiving the second dose. A finding that vaccinated individuals were much more likely to be infected than unvaccinated individuals in the period 0-13 days after first dose (aOR 2.11, 95% CI 1.36-3.27) suggests that unmeasured confounding led to downward bias in the vaccine effectiveness estimate. Interpretation Evidence from this test-negative study of the effectiveness of CoronaVac was mixed, and likely affected by bias in this setting. Administration of at least one vaccine dose showed effectiveness against symptomatic SARS-CoV-2 infection in the setting of epidemic Gamma variant transmission. However, the low estimated effectiveness of the two-dose schedule underscores the need to maintain non-pharmaceutical interventions while vaccination campaigns with CoronaVac are being implemented. Funding Fundacao Oswaldo Cruz (Fiocruz); Municipal Health Secretary of Manaus; Fundacao de Vigilância em Saude do Amazonas

Investigation of SARS-CoV-2 infection in dogs and cats of humans diagnosed with COVID-19 in Rio de Janeiro, Brazil.

Abstract: BACKGROUND: Infection by SARS-CoV-2 in domestic animals has been related to close contact with humans diagnosed with COVID-19. Objectives: To assess the exposure, infection, and persistence by SARS-CoV-2 of dogs and cats living in the same households of humans that tested positive for SARS-CoV-2, and to investigate clinical and laboratory alterations associated with animal infection. METHODS: Animals living with COVID-19 patients were longitudinally followed and had nasopharyngeal/oropharyngeal and rectal swabs collected and tested for SARS-CoV-2. Additionally, blood samples were collected for laboratory analysis, and plaque reduction neutralization test (PRNT90) to investigate specific SARS-CoV-2 antibodies. RESULTS: Between May and October 2020, 39 pets (29 dogs and 10 cats) of 21 patients were investigated. Nine dogs (31%) and four cats (40%) from 10 (47.6%) households were infected with or seropositive for SARS-CoV-2. Animals tested positive from 11 to 51 days after the human index COVID-19 case onset of symptoms. Three dogs tested positive twice within 14, 30, and 31 days apart. SARS-CoV-2 neutralizing antibodies were detected in one dog (3.4%) and two cats (20%). In this study, six out of thirteen animals either infected with or seropositive for SARS-CoV-2 have developed mild but reversible signs of the disease. Using logistic regression analysis, neutering, and sharing bed with the ill owner were associated with pet infection. CONCLUSIONS: The presence and persistence of SARS-CoV-2 infection have been identified in dogs and cats from households with human COVID-19 cases in Rio de Janeiro, Brazil. People with COVID-19 should avoid close contact with their pets during the time of their illness.

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight

Abstract: From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions.

Pathological findings in organs and tissues of patients with COVID-19: A systematic review.

Abstract: BACKGROUND: Coronavirus disease (COVID-19) is the pandemic caused by SARS-CoV-2 that has caused more than 2.2 million deaths worldwide. We summarize the reported pathologic findings on biopsy and autopsy in patients with severe/fatal COVID-19 and documented the presence and/or effect of SARS-CoV-2 in all organs. METHODS AND FINDINGS: A systematic search of the PubMed, Embase, MedRxiv, Lilacs and Epistemonikos databases from January to August 2020 for all case reports and case series that reported histopathologic findings of COVID-19 infection at autopsy or tissue biopsy was performed. 603 COVID-19 cases from 75 of 451 screened studies met inclusion criteria. The most common pathologic findings were lungs: diffuse alveolar damage (DAD) (92%) and superimposed acute bronchopneumonia (27%); liver: hepatitis (21%), heart: myocarditis (11.4%). Vasculitis was common only in skin biopsies (25%). Microthrombi were described in the placenta (57.9%), lung (38%), kidney (20%), Central Nervous System (CNS) (18%), and gastrointestinal (GI) tract (2%). Injury of endothelial cells was common in the lung (18%) and heart (4%). Hemodynamic changes such as necrosis due to hypoxia/hypoperfusion, edema and congestion were common in kidney (53%), liver (48%), CNS (31%) and GI tract (18%). SARS-CoV-2 viral particles were demonstrated within organ-specific cells in the trachea, lung, liver, large intestine, kidney, CNS either by electron microscopy, immunofluorescence, or immunohistochemistry. Additional tissues were positive by Polymerase Chain Reaction (PCR) tests only. The included studies were from numerous countries, some were not peer reviewed, and some studies were performed by subspecialists, resulting in variable and inconsistent reporting or over statement of the reported findings. CONCLUSIONS: The main pathologic findings of severe/fatal COVID-19 infection are DAD, changes related to coagulopathy and/or hemodynamic compromise. In addition, according to the observed organ damage myocarditis may be associated with sequelae.

Global burden of influenza-associated lower respiratory tract infections and hospitalizations among adults: A systematic review and meta-analysis

Abstract: Background Influenza illness burden is substantial, particularly among young children, older adults, and those with underlying conditions. Initiatives are underway to develop better global estimates for influenza-associated hospitalizations and deaths. Knowledge gaps remain regarding the role of influenza viruses in severe respiratory disease and hospitalizations among adults, particularly in lower-income settings. Methods and findings We aggregated published data from a systematic review and unpublished data from surveillance platforms to generate global meta-analytic estimates for the proportion of acute respiratory hospitalizations associated with influenza viruses among adults. We searched 9 online databases (Medline, Embase, CINAHL, Cochrane Library, Scopus, Global Health, LILACS, WHOLIS, and CNKI; 1 January 1996–31 December 2016) to identify observational studies of influenza-associated hospitalizations in adults, and assessed eligible papers for bias using a simplified Newcastle–Ottawa scale for observational data. We applied meta-analytic proportions to global estimates of lower respiratory infections (LRIs) and hospitalizations from the Global Burden of Disease study in adults ≥20 years and by age groups (20–64 years and ≥65 years) to obtain the number of influenza-associated LRI episodes and hospitalizations for 2016. Data from 63 sources showed that influenza was associated with 14.1% (95% CI 12.1%–16.5%) of acute respiratory hospitalizations among all adults, with no significant differences by age group. The 63 data sources represent published observational studies (n = 28) and unpublished surveillance data (n = 35), from all World Health Organization regions (Africa, n = 8; Americas, n = 11; Eastern Mediterranean, n = 7; Europe, n = 8; Southeast Asia, n = 11; Western Pacific, n = 18). Data quality for published data sources was predominantly moderate or high (75%, n = 56/75). We estimate 32,126,000 (95% CI 20,484,000–46,129,000) influenza-associated LRI episodes and 5,678,000 (95% CI 3,205,000–9,432,000) LRI hospitalizations occur each year among adults. While adults <65 years contribute most influenza-associated LRI hospitalizations and episodes (3,464,000 [95% CI 1,885,000–5,978,000] LRI hospitalizations and 31,087,000 [95% CI 19,987,000–44,444,000] LRI episodes), hospitalization rates were highest in those ≥65 years (437/100,000 person-years [95% CI 265–612/100,000 person-years]). For this analysis, published articles were limited in their inclusion of stratified testing data by year and age group. Lack of information regarding influenza vaccination of the study population was also a limitation across both types of data sources. Conclusions In this meta-analysis, we estimated that influenza viruses are associated with over 5 million hospitalizations worldwide per year. Inclusion of both published and unpublished findings allowed for increased power to generate stratified estimates, and improved representation from lower-income countries. Together, the available data demonstrate the importance of influenza viruses as a cause of severe disease and hospitalizations in younger and older adults worldwide.

The COVID-19 Infodemic

Abstract: Official English translation from the original Spanish manuscript made by the Pan American Health Organization. In case of discrepancy, the original version (Spanish) shall prevail.

WHO global antimicrobial resistance surveillance for Neisseria gonorrhoeae 2017–18: a retrospective observational study

Abstract: Summary Background Gonorrhoea and antimicrobial resistance (AMR) in Neisseria gonorrhoeae are major health concerns globally. Increased global surveillance of gonococcal AMR is essential. We aimed to describe the 2017–18 data from WHO's global gonococcal AMR surveillance, and to discuss priorities essential for the effective management and control of gonorrhoea. Methods We did a retrospective observational study of the AMR data of gonococcal isolates reported to WHO by 73 countries in 2017–18. WHO recommends that each country collects at least 100 gonococcal isolates per year, and that quantitative methods to determine the minimum inhibitory concentration of antimicrobials, interpreted by internationally standardised resistance breakpoints, are used. Findings In 2017–18, 73 countries provided AMR data for one or more drug. Decreased susceptibility or resistance to ceftriaxone was reported by 21 (31%) of 68 reporting countries and to cefixime by 24 (47%) of 51 reporting countries. Resistance to azithromycin was reported by 51 (84%) of 61 reporting countries and to ciprofloxacin by all 70 (100%) reporting countries. The annual proportion of decreased susceptibility or resistance across countries was 0–21% to ceftriaxone and 0–22% to cefixime, and that of resistance was 0–60% to azithromycin and 0–100% to ciprofloxacin. The number of countries reporting gonococcal AMR and resistant isolates, and the number of examined isolates, have increased since 2015–16. Surveillance remains scarce in central America and the Caribbean and eastern Europe, and in the WHO African, Eastern Mediterranean, and South-East Asian regions. Interpretation In many countries, ciprofloxacin resistance was exceedingly high, azithromycin resistance was increasing, and decreased susceptibility or resistance to ceftriaxone and cefixime continued to emerge. WHO's global surveillance of gonococcal AMR needs to expand internationally to provide imperative data for national and international management guidelines and public health policies. Improved prevention, early diagnosis, treatment of index patients and partners, enhanced surveillance (eg, infection, AMR, treatment failures, and antimicrobial use or misuse), and increased knowledge on antimicrobial selection, stewardship, and pharmacokinetics or pharmacodynamics are essential. The development of rapid, accurate, and affordable point-of-care gonococcal diagnostic tests, new antimicrobials, and gonococcal vaccines is imperative. Funding None.

Evolutionary Dynamics and Dissemination Pattern of the SARS-CoV-2 Lineage B.1.1.33 During the Early Pandemic Phase in Brazil

Abstract: We would like to thank the funding support from CGLab/MoH (General Laboratories Coordination of Brazilian Ministry of Health), CVSLR/FIOCRUZ (Coordination of Health Surveillance and Reference Laboratories of Oswaldo Cruz Foundation), CNPq COVID-19 MCTI 402457/2020-0, and INOVA VPPCB-005-FIO20-2

Effectiveness of ChAdOx1 vaccine in older adults during SARS-CoV-2 Gamma variant circulation in São Paulo.

Abstract: A two-dose regimen of the Oxford-AstraZeneca (ChAdOx1) Covid-19 vaccine with an inter-dose interval of three months has been implemented in many countries with restricted vaccine supply. However, there is limited evidence for the effectiveness of ChAdOx1 by dose in elderly populations in countries with high prevalence of the Gamma variant of SARS-CoV-2. Here, we estimate ChAdOx1 effectiveness by dose against the primary endpoint of RT-PCR-confirmed Covid-19, and secondary endpoints of Covid-19 hospitalization and Covid-19-related death, in adults aged ≥60 years during an epidemic with high Gamma variant prevalence in Sao Paulo state, Brazil using a matched, test-negative case-control study. Starting 28 days after the first dose, effectiveness of a single dose of ChAdOx1 is 33.4% (95% CI, 26.4-39.7) against Covid-19, 55.1% (95% CI, 46.6-62.2) against hospitalization, and 61.8% (95% CI, 48.9-71.4) against death. Starting 14 days after the second dose, effectiveness of the two-dose schedule is 77.9% (95% CI, 69.2-84.2) against Covid-19, 87.6% (95% CI, 78.2-92.9) against hospitalization, and 93.6% (95% CI, 81.9-97.7) against death. Completion of the ChAdOx1 vaccine schedule affords significantly increased protection over a single dose against mild and severe Covid-19 outcomes in elderly individuals during widespread Gamma variant circulation.

Effectiveness of CoronaVac in the setting of high SARS-CoV-2 P.1 variant transmission in Brazil: A test-negative case-control study

Abstract: Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant P.1 emerged in the city of Manaus in late 2020 during a large resurgence of coronavirus disease (COVID-19), and has spread throughout Brazil. The effectiveness of vaccines in settings with widespread P.1 transmission has not been reported. Methods We performed a matched test-negative case-control study to estimate the effectiveness of an inactivated vaccine, CoronaVac, in healthcare workers (HCWs) in Manaus, where P.1 accounted for 75% of genotyped SARS-CoV-2 samples at the peak of its epidemic. Information from electronic surveillance databases was used to select cases of RT-PCR-confirmed SARS-CoV-2 infection and matched test-negative controls from 19 January, 2021 to 25 March, 2021. We used conditional logistic regression to estimate the effectiveness in reducing the odds of primary and secondary outcomes of, respectively, symptomatic and any SARS-CoV-2 infection. Findings Among 53,176 HCWs, 46,884 (88%) received at least one dose of CoronaVac and 2,656 (5%) underwent RT-PCR testing from 19 January, 2021 to 25 March, 2021. Of 2,797 RT-PCR tests, 776 (28%) were positive. 393 and 135 case-control pairs with and without, respectively, symptomatic illness were selected for the matched analyses. Vaccination with at least one dose was associated with a 0.50-fold reduction (adjusted vaccine effectiveness, 49.6%; 95% CI, 11.3 - 71.4) in the odds of symptomatic SARS-CoV-2 infection during the period 14 days or more after receiving the first dose. Estimated vaccine effectiveness of at least one dose against any SARS-CoV-2 infection was 35.1% (95% CI, −6.6 - 60.5) in the same time period. Interpretation Administration of at least one dose of CoronaVac showed effectiveness against symptomatic SARS-CoV-2 infection in the setting of epidemic P.1 transmission, underscoring the need to increase vaccination efforts in response to the spread of this variant in Brazil and globally. Funding Pan American Health Organization; Fundacao Oswaldo Cruz (Fiocruz); Municipal Health Secretary of Manaus

Depressive symptoms among Peruvian adult residents amidst a National Lockdown during the COVID-19 pandemic.

Abstract: Population health and well-being in Latin America, the current epicenter of the COVID-19 pandemic, has been severely affected during the past semester. Despite the growing evidence about the link between the pandemic, its control measures, and mental health worldwide, there is still no regional evidence of the potential mental health impact. We describe the prevalence and distribution of depressive symptoms across demographic and socioeconomic risk factors in the Peruvian population amidst a national lockdown during the COVID-19 pandemic. Cross-sectional study conducted during the community transmission phase and national lockdown in Peru (May 4th–16th, 2020). We recorded 64,493 responses from adult Peruvian residents through an opt-in online questionnaire. All analyses were weighted using raking based on proportions of sociodemographic variables from the last Peruvian census in 2017. The prevalence of depressive symptoms was calculated using the Patient Health Questionnaire (PHQ-9) score of 10 or more. We identified associated demographic and socioeconomic factors by prior mental health diagnosis. Sensitivity analysis considered an alternative cut-off point for depressive symptoms of PHQ-9 ≥ 14. A total of 57,446 participants were included in the analytical sample. A third of the participants (n = 23,526, unweighted) showed depressive symptoms in the 2 weeks prior to the study. Participants who reported a previous mental health diagnosis doubled the sample prevalence of depressive symptoms (59, 95%CI 56.7, 61.4%) of those without a prior diagnosis. Psychosocial and functioning reactions were largely more prevalent among females and young adults. A dose-response relationship was found between household income and depressive symptoms across previous mental health diagnosis strata, being as low as 32% less in the wealthiest than the most impoverished group (PR: 0.68, 95%CI 0.58,0.79). Other critical factors associated with a higher burden of depressive symptoms were lower education level, single, unemployed, and chronic comorbidity. An increased burden of depressive symptoms and psychosocial reactions has emerged during the COVID-19 pandemic in Peru compared to previous years. The mental health burden disproportionately affects women, the younger population, and those with low income and education. As the country eases the social distancing measures, it is crucial to use local evidence to adjust public health policies and mental health services to the renewed population needs.

Alcohol use during the COVID-19 pandemic in Latin America and the Caribbean

Abstract: Objective. To assess the association between drinking behaviors during the COVID-19 pandemic and quarantine, anxiety symptoms, and sociodemographic characteristics in Latin America and the Caribbean (LAC). Method. Data was collected through a cross-sectional online survey (non-probabilistic sample) conducted by the Pan American Health Organization between May 22 and June 30, 2020, in 33 countries and two territories of LAC. Participants were 18 years of age or older and must not have traveled outside of their country since March 15, 2020 (n= 12 328, M age= 38.1 years, 65% female). Four drinking behaviors (online socializing drinking [OSD], drinking with child present [DCP], drinking before 5 p.m. [DB5]), heavy episodic drinking [HED]) were response variables, and quarantining, anxiety symptoms and sociodemographic covariables were explanatory variables. Results. Quarantine was positively associated with a higher frequency of OSD and with DCP, but negatively associated with a higher frequency of HED. Anxiety symptoms were associated with a higher frequency of HED, more OSD, and DB5. Higher incomes seemed to be more associated with all the studied drinking behaviors. Women tended to report less DB5 and less HED during the pandemic. Conclusions. Quarantine during the COVID-19 pandemic seems to affect drinking behavior and mental health indicators like anxiety symptoms. This study is the first effort to measure the consequences of the quarantine on alcohol consumption and mental health in LAC during the COVID-19 pandemic. Considering the associations found, screenings and brief interventions targeting alcohol consumption and mental health are recommended.

COVID-19 in pediatric cancer patients in a resource-limited setting: National data from Peru.

Abstract: To the Editor: Peru, an upper-middle income country according to theWorldBank, is being severely affected by the COVID-19 pandemic, counting today 285 213 cases and 9677 deaths, and having one of the highest incidence rates of COVID-19 in the world (87.5 per million inhabitants).1 National lockdown policies, transportation restriction, and economic constrains, alongwith disrupted health care services, have significantly impacted access for diagnosis and treatment of childrenwith cancer.2,3 Although recent papers suggest that the pediatric oncology population may not have higher mortality resulting from SARS-CoV-2 infection in high-income countries (Spain,4 China,5 USA,6 Italy7), these patients would be a potential vulnerable group for worse outcomes,8 especially in lowandmiddle-income countries (LMIC). We report 69 pediatric cancer patients (ages 0-16 years) diagnosed with SARS CoV-2 infection from March 6 to July 7, 2020 from six tertiary centers in Peru (National Institute of Neoplastic Diseases, Rebagliati Hospital, Almenara Hospital, and National Institute of Children San Borja in Lima; and two hospitals from Trujillo and Chiclayo) and three cancer shelters in Lima. The main patient characteristics are shown in Table 1. The cancer types included hematological malignancies (69%) and solid tumors (31%). Most patients were treated as ambulatory and interestingly, 20 (29%) were already hospitalized suspected of a potential nosocomial SARS-CoV-2 infection source. The most frequent symptomswere fever and cough (66.67%). Thirty-seven patients were asymptomatic (53.7%). Chemotherapy was stopped in all cases. COVID-19 treatment was based on ivermectin, azithromycin, and corticosteroids in nine cases, whereas 60 patients did not receive any treatment. At the time of this report, 62 patients are alivewith no complications due to SARS CoV-2 and seven are dead. Four patients had progressive disease and complications not related with COVID-19 and the rest (three patients) had severe pneumonia with rapid deterioration despite intensive care in one case or unavailable ICU beds in two cases. Patients under noncurative treatmentwere atmore risk of death due to COVID-19 (chi-square, P = .004) than patients under curative treatment. In our cohort, COVID-19 lethality is 10%, much higher than documented for the general pediatric population in Peru (0.34%)1 or other countries.9,10 COVID-19 infection in childrenwith cancer has generatednewchallenges in pediatric oncology worldwide, especially in limited resource settings. It is important to maintain pediatric cancer treatment as a priority; however, some factors such as the increasing number of TABLE 1 Characteristics of study sample

Effectiveness of the CoronaVac vaccine in the elderly population during a P.1 variant-associated epidemic of COVID-19 in Brazil: A test-negative case-control study

Abstract: Background Mass vaccination is being used in response to coronavirus disease (COVID-19) epidemics, including those driven by emerging variants of concern. We evaluated the effectiveness of the inactivated whole-virus vaccine, CoronaVac, against symptomatic COVID-19 in the elderly population of Sao Paulo State, Brazil during widespread circulation of the P.1 variant. Methods We conducted a test-negative, case-control study of adults ≥70 years of age from Sao Paulo State from January 17 to April 29, 2021, during which vaccination with a two-dose regimen of CoronaVac was implemented. We identified RT-PCR-confirmed COVID-19 cases as well as controls who had a symptomatic illness with a negative RT-PCR test from national surveillance and state vaccination databases. Controls were pair-matched to cases by age category, sex, self-report race, municipality, prior COVID-19 status, and date of RT-PCR testing. We estimated vaccine effectiveness, adjusted for age and comorbidities, using conditional logistic regression. Findings We selected 7,950 matched pairs with a mean age of 76 years from 26,433 COVID-19 cases and 17,622 test-negative controls. Adjusted vaccine effectiveness was 18.2% (95% CI, 0.0 to 33.2) and 41.6% (95% CI, 26.9 to 53.3) in the period 0-13 and ≥14 days, respectively, after the 2nd dose. Administration of a single vaccine dose was not associated with reduced odds of COVID-19. Vaccine effectiveness ≥14 days after the 2nd dose declined with increasing age and was 61.8% (95% CI 34.8 to 77.7), 48.9% (95% CI 23.3 to 66.0) and 28.0% (95% CI 0.6 to 47.9) among individuals 70-74, 75-79 and ≥80 years of age, respectively (pinteraction = 0.05). Interpretation CoronaVac was 42% effective in the real-world setting of extensive P.1 transmission, but significant protection was not observed until completion of the two-dose regimen and vaccine effectiveness declined with increasing age. These findings underscore the need to maintain non-pharmaceutical interventions when mass vaccination with CoronaVac is used as part of an epidemic response. Funding Pan American Health Organization. Research in context Evidence before this study We searched Pubmed for articles published from inception of the pandemic until May 10, 2021, with no language restrictions, using the search terms “vaccine”, “COVID-19”, “SARS-CoV-2”, “elderly”, “age”, “older”. Randomised controlled trials (RCTs) have yielded varying estimates (51-84%) for the effectiveness of the inactivated whole-virus vaccine, CoronaVac, against symptomatic COVID-19. Current evidence is lacking on whether CoronaVac or other COVID-19 vaccines are effective against disease caused by the SARS-CoV-2 variant of concern, P.1, or in a setting of extensive P.1 circulation. No studies have reported the real-world effectiveness of CoronaVac and other inactivated vaccines among elderly individuals, a population that was underrepresented in RCTs of these vaccines. Added value of this study In a population-based matched test-negative case-control study, we found that a two-dose regimen of CoronaVac had an effectiveness of 42% in preventing symptomatic COVID-19 among adults ≥70 years of age during an epidemic associated with widespread P.1 variant transmission. Significant protection was not observed until the period ≥14 days after administration of the second dose. We observed a significant decline in vaccine effectiveness with increasing age in the elderly population. Implications of all the available evidence In the setting of extensive P.1 transmission, the effectiveness of CoronaVac in adults ≥70 years of age was similar to that observed in RCTs conducted in younger populations prior to the emergence of P.1. These findings provide supportive evidence for the use of this vaccine in countries that are experiencing P.1-associated epidemics. However, significant protection was not detected until after administration of the second dose, indicating that vaccination in countries where CoronaVac supplies are constrained may need to prioritize completion of the two dose regimen among the highest risk populations. The delay in achieving vaccine-mediated protection also underscores the need to initiate and maintain non-pharmaceutical interventions when mass vaccination with CoronaVac is used in a response to an epidemic. National immunisation programs should optimise the vaccination of the very elderly (≥80 years), accounting for specific vaccines or vaccination schemes.

The history of foot-and-mouth disease virus serotype C: the first known extinct serotype?

Abstract: Foot-and-mouth disease (FMD) is a highly contagious animal disease caused by an RNA virus subdivided into seven serotypes that are unevenly distributed in Asia, Africa, and South America. Despite the challenges of controlling FMD, since 1996 there have been only two outbreaks attributed to serotype C, in Brazil and in Kenya, in 2004. This article describes the historical distribution and origins of serotype C and its disappearance. The serotype was first described in Europe in the 1920s, where it mainly affected pigs and cattle but as a less common cause of outbreaks than serotypes O and A. No serotype C outbreaks have been reported in Europe since vaccination stopped in 1990. FMD virus is presumed to have been introduced into South America from Europe in the nineteenth century, although whether serotype C evolved there or in Europe is not known. As in Europe, this serotype was less widely distributed and caused fewer outbreaks than serotypes O and A. Since 1994, serotype C had not been reported from South America until four small outbreaks were detected in the Amazon region in 2004. Elsewhere, serotype C was introduced to Asia, in the 1950s to the 1970s, persisting and evolving for several decades in the Indian subcontinent and for eighteen years in the Philippines. Serotype C virus also circulated in East Africa between 1957 and 2004. Many serotype C viruses from European and Kenyan outbreaks were closely related to vaccine strains, including the most recently recovered Kenyan isolate from 2004. International surveillance has not confirmed any serotype C cases, worldwide, for over 15 years, despite more than 2,000 clinical submissions per year to reference laboratories. Serology provides limited evidence for absence of this serotype, as unequivocal interpretation is hampered by incomplete intra-serotype specificity of immunoassays and the continued use of this serotype in vaccines. It is recommended to continue strengthening surveillance in regions of FMD endemicity, to stop vaccination against serotype C and to reduce working with the virus in laboratories, since inadvertent escape of virus during such activities is now the biggest risk for its reappearance in the field.