SARS-CoV-2 Breakthrough Infections among US Embassy Staff Members, Uganda, May-June 2021.

The SARS-CoV-2 Delta variant emerged shortly after COVID-19 vaccines became available in 2021. We describe SARS-CoV-2 breakthrough infections in a highly vaccinated, well-monitored US Embassy community in Kampala, Uganda. Defining breakthrough infection rates in highly vaccinated populations can help determine public health messaging, guidance, and policy globally.

Cluster of SARS-CoV-2 Gamma Variant Infections, Parintins, Brazil, March 2021.

High case counts after the Gamma (P. 1) variant of severe acute respiratory syndrome coronavirus 2 emerged in Brazil raised concerns that previously infected persons might become reinfected. Investigation of a cluster of coronavirus disease cases in Parintins, in the Brazilian Amazon, suggested household transmission but did not identify high rates of reinfection.

Lessons Learned from CDC's Global COVID-19 Early Warning and Response Surveillance System.

Early warning and response surveillance (EWARS) systems were widely used during the early COVID-19 response. Evaluating the effectiveness of EWARS systems is critical to ensuring global health security. We describe the Centers for Disease Control and Prevention (CDC) global COVID-19 EWARS (CDC EWARS) system and the resources CDC used to gather, manage, and analyze publicly available data during the prepandemic period. We evaluated data quality and validity by measuring reporting completeness and compared these with data from Johns Hopkins University, the European Centre for Disease Prevention and Control, and indicator-based data from the World Health Organization. CDC EWARS was integral in guiding CDC's early COVID-19 response but was labor-intensive and became less informative as case-level data decreased and the pandemic evolved. However, CDC EWARS data were similar to those reported by other organizations, confirming the validity of each system and suggesting collaboration could improve EWARS systems during future pandemics.

Active surveillance and early detection of community transmission of SARS-CoV-2 Mu variant (B.1.621) in the Brazilian Amazon.

Through active surveillance and contact tracing from outpatients, we aimed to identify and characterize SARS-CoV-2 variants circulating in Porto Velho-Rondônia, a city in the Brazilian Amazon. As part of a prospective cohort, we gathered information from 2,506 individuals among COVID-19 patients and household contacts. Epidemiological data, nasopharyngeal swabs, and blood samples were collected from all participants. Nasopharyngeal swabs were tested for antigen rapid diagnostic test and reverse transcription-polymerase chain reaction (RT-PCR) followed by genomic sequencing. Blood samples underwent ELISA testing for IgA, IgG, and IgM antibody levels. From 757 specimens sequenced, three were identified as Mu variant, none of the individuals carrying this variant had a travel history in the previous 15 days before diagnosis. One case was asymptomatic and two presented mild symptoms. Two infected individuals from different households caring viruses with additional amino acid substitutions ORF7a P45L and ORF1a T1055A compared to the Mu virus reference sequence. One patient presented IgG levels. Our results highlight that genomic surveillance for SARS-CoV-2 variants can assist in detecting the emergency of SARS-CoV-2 variants in the community, before its identification in other parts of the country.

COVID-19 Mortality and Vaccine Coverage - Hong Kong Special Administrative Region, China, January 6, 2022-March 21, 2022.

On January 6, 2022, a cluster of COVID-19 cases* caused by the Omicron variant of SARS-CoV-2, the virus that causes COVID-19, was detected in Hong Kong Special Administrative Region, China (Hong Kong), resulting in the territory's fifth wave of COVID-19 cases (1). This wave peaked on March 4, 2022, with 8,764 COVID-19 cases per million population (2), resulting in a total of 1,049,959 cases and 5,906 COVID-19-associated deaths reported to the Hong Kong Department of Health during January 6-March 21, 2022.† Throughout this period, the COVID-19 mortality rate in Hong Kong (37.7 per million population) was among the highest reported worldwide since the COVID-19 pandemic began (3). Publicly available data on age-specific vaccination coverage in Hong Kong with a 2-dose primary vaccination series (with either Sinovac-CoronaVac [Sinovac], an inactivated COVID-19 viral vaccine, recommended for persons aged ≥3 years or BNT162b2 [Pfizer-BioNTech], an mRNA vaccine, for persons aged ≥5 years), as of December 23, 2021,§,¶ and COVID-19 mortality during January 6-March 21, 2022, were analyzed. By December 23, 2021, 67% of vaccine-eligible persons in Hong Kong had received ≥1 dose of a COVID-19 vaccine, 64% had received ≥2 doses, and 5% had received a booster dose. Among persons aged ≥60 years, these proportions were 52%, 49%, and 7%, respectively. Among those aged ≥60 years, vaccination coverage declined with age: 48% of persons aged 70-79 years had received ≥1 dose, 45% received ≥2 doses, and 7% had received a booster, and among those aged ≥80 years, 20%, 18%, and 2% had received ≥1 dose, ≥2 doses, and a booster dose, respectively. Among 5,906 COVID-19 deaths reported, 5,655 (96%) occurred in persons aged ≥60 years**; among these decedents, 3,970 (70%) were unvaccinated, 18% (1,023) had received 1 vaccine dose, and 12% (662) had received ≥2 doses. The overall rates of COVID-19-associated mortality among persons aged ≥60 years who were unvaccinated, who had received 1 COVID-19 vaccine dose, and who had received ≥2 vaccine doses were 10,076, 1,099, and 473 per million population, respectively; the risk for COVID-19-associated death among unvaccinated persons was 21.3 times that among recipients of 2-3 doses in this age group. The high overall mortality rate during the ongoing 2022 Hong Kong Omicron COVID-19 outbreak is being driven by deaths among unvaccinated persons aged ≥60 years. Efforts to identify and address gaps in age-specific vaccination coverage can help prevent high mortality from COVID-19, especially among persons aged ≥60 years.

Coronavirus Disease 2019 (COVID-19) in Americans Aboard the Diamond Princess Cruise Ship.

BACKGROUND: The Diamond Princess cruise ship was the site of a large outbreak of coronavirus disease 2019 (COVID-19). Of 437 Americans and their travel companions on the ship, 114 (26%) tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: We interviewed 229 American passengers and crew after disembarkation following a ship-based quarantine to identify risk factors for infection and characterize transmission onboard the ship. RESULTS: The attack rate for passengers in single-person cabins or without infected cabinmates was 18% (58/329), compared with 63% (27/43) for those sharing a cabin with an asymptomatic infected cabinmate, and 81% (25/31) for those with a symptomatic infected cabinmate. Whole genome sequences from specimens from passengers who shared cabins clustered together. Of 66 SARS-CoV-2-positive American travelers with complete symptom information, 14 (21%) were asymptomatic while on the ship. Among SARS-CoV-2-positive Americans, 10 (9%) required intensive care, of whom 7 were ≥70 years. CONCLUSIONS: Our findings highlight the high risk of SARS-CoV-2 transmission on cruise ships. High rates of SARS-CoV-2 positivity in cabinmates of individuals with asymptomatic infections suggest that triage by symptom status in shared quarters is insufficient to halt transmission. A high rate of intensive care unit admission among older individuals complicates the prospect of future cruise travel during the pandemic, given typical cruise passenger demographics. The magnitude and severe outcomes of this outbreak were major factors contributing to the Centers for Disease Control and Prevention's decision to halt cruise ship travel in US waters in March 2020.

Use of US Public Health Travel Restrictions during COVID-19 Outbreak on Diamond Princess Ship, Japan, February-April 2020.

Public health travel restrictions (PHTR) are crucial measures during communicable disease outbreaks to prevent transmission during commercial airline travel and mitigate cross-border importation and spread. We evaluated PHTR implementation for US citizens on the Diamond Princess during its coronavirus disease (COVID-19) outbreak in Japan in February 2020 to explore how PHTR reduced importation of COVID-19 to the United States during the early phase of disease containment. Using PHTR required substantial collaboration among the US Centers for Disease Control and Prevention, other US government agencies, the cruise line, and public health authorities in Japan. Original US PHTR removal criteria were modified to reflect international testing protocols and enable removal of PHTR for persons who recovered from illness. The impact of PHTR on epidemic trajectory depends on the risk for transmission during travel and geographic spread of disease. Lessons learned from the Diamond Princess outbreak provide critical information for future PHTR use.

Cross-Reactivity of Two SARS-CoV-2 Serological Assays in a Setting Where Malaria Is Endemic.

Accurate SARS-CoV-2 serological assays are critical for COVID-19 serosurveillance. However, previous studies have indicated possible cross-reactivity of these assays, including in areas where malaria is endemic. We tested 213 well-characterized prepandemic samples from Nigeria using two SARS-CoV-2 serological assays, Abbott Architect IgG and Euroimmun NCP IgG assay, both targeting SARS-CoV-2 nucleocapsid protein. To assess antibody binding strength, an avidity assay was performed on these samples and on plasma from SARS-CoV-2 PCR-positive persons. Thirteen (6.1%) of 212 samples run on the Abbott assay and 38 (17.8%) of 213 run on the Euroimmun assay were positive. Anti-Plasmodium IgG levels were significantly higher among false positives for both Abbott and Euroimmun; no association was found with active Plasmodium falciparum infection. An avidity assay using various concentrations of urea wash in the Euroimmun assay reduced loosely bound IgG: of 37 positive/borderline prepandemic samples, 46%, 86%, 89%, and 97% became negative using 2 M, 4 M, 5 M, and 8 M urea washes, respectively. The wash slightly reduced avidity of antibodies from SARS-CoV-2 patients within 28 days of PCR confirmation; thereafter, avidity increased for all urea concentrations except 8 M. This validation found moderate to substantial cross-reactivity on two SARS-CoV-2 serological assays using samples from a setting where malaria is endemic. A simple urea wash appeared to alleviate issues of cross-reactivity.

Evidence of behaviour change during an Ebola virus disease outbreak, Sierra Leone.

OBJECTIVE: To evaluate changes in Ebola-related knowledge, attitudes and prevention practices during the Sierra Leone outbreak between 2014 and 2015. METHODS: Four cluster surveys were conducted: two before the outbreak peak (3499 participants) and two after (7104 participants). We assessed the effect of temporal and geographical factors on 16 knowledge, attitude and practice outcomes. FINDINGS: Fourteen of 16 knowledge, attitude and prevention practice outcomes improved across all regions from before to after the outbreak peak. The proportion of respondents willing to: (i) welcome Ebola survivors back into the community increased from 60.0% to 89.4% (adjusted odds ratio, aOR: 6.0; 95% confidence interval, CI: 3.9-9.1); and (ii) wait for a burial team following a relative's death increased from 86.0% to 95.9% (aOR: 4.4; 95% CI: 3.2-6.0). The proportion avoiding unsafe traditional burials increased from 27.3% to 48.2% (aOR: 3.1; 95% CI: 2.4-4.2) and the proportion believing spiritual healers can treat Ebola decreased from 15.9% to 5.0% (aOR: 0.2; 95% CI: 0.1-0.3). The likelihood respondents would wait for burial teams increased more in high-transmission (aOR: 6.2; 95% CI: 4.2-9.1) than low-transmission (aOR: 2.3; 95% CI: 1.4-3.8) regions. Self-reported avoidance of physical contact with corpses increased in high but not low-transmission regions, aOR: 1.9 (95% CI: 1.4-2.5) and aOR: 0.8 (95% CI: 0.6-1.2), respectively. CONCLUSION: Ebola knowledge, attitudes and prevention practices improved during the Sierra Leone outbreak, especially in high-transmission regions. Behaviourally-targeted community engagement should be prioritized early during outbreaks.

Public Health Responses to COVID-19 Outbreaks on Cruise Ships - Worldwide, February-March 2020.

An estimated 30 million passengers are transported on 272 cruise ships worldwide each year* (1). Cruise ships bring diverse populations into proximity for many days, facilitating transmission of respiratory illness (2). SARS-CoV-2, the virus that causes coronavirus disease (COVID-19) was first identified in Wuhan, China, in December 2019 and has since spread worldwide to at least 187 countries and territories. Widespread COVID-19 transmission on cruise ships has been reported as well (3). Passengers on certain cruise ship voyages might be aged ≥65 years, which places them at greater risk for severe consequences of SARS-CoV-2 infection (4). During February-March 2020, COVID-19 outbreaks associated with three cruise ship voyages have caused more than 800 laboratory-confirmed cases among passengers and crew, including 10 deaths. Transmission occurred across multiple voyages of several ships. This report describes public health responses to COVID-19 outbreaks on these ships. COVID-19 on cruise ships poses a risk for rapid spread of disease, causing outbreaks in a vulnerable population, and aggressive efforts are required to contain spread. All persons should defer all cruise travel worldwide during the COVID-19 pandemic.

Ebola Virus Infection Associated with Transmission from Survivors.

Ebola virus (EBOV) can persist in immunologically protected body sites in survivors of Ebola virus disease, creating the potential to initiate new chains of transmission. From the outbreak in West Africa during 2014-2016, we identified 13 possible events of viral persistence-derived transmission of EBOV (VPDTe) and applied predefined criteria to classify transmission events based on the strength of evidence for VPDTe and source and route of transmission. For 8 events, a recipient case was identified; possible source cases were identified for 5 of these 8. For 5 events, a recipient case or chain of transmission could not be confidently determined. Five events met our criteria for sexual transmission (male-to-female). One VPDTe event led to at least 4 generations of cases; transmission was limited after the other events. VPDTe has increased the importance of Ebola survivor services and sustained surveillance and response capacity in regions with previously widespread transmission.

Ebola: Anatomy of an Epidemic.

As of the end of March 2016, the West Africa epidemic of Ebola virus disease (Ebola) had resulted in a total of 28,646 cases, 11,323 of them fatal, reported to the World Health Organization. Guinea, Liberia, and Sierra Leone were most heavily affected, but Ebola cases were exported to several other African and European countries as well as the United States, with limited further transmission, including to healthcare workers. We review the descriptive epidemiology of the outbreak, novel aspects and insights concerning the unprecedented response, scientific observations, and public health implications. The large number of Ebola survivors has highlighted the frequency of persistent symptoms and the possibility of virus persistence in sanctuary sites, sometimes leading to delayed transmission. Although transmission appears to have ceased in 2016, the West Africa Ebola epidemic has profoundly influenced discussions and practice concerning global health security.

Adherence to Ebola-specific malaria case management guidelines at health facilities in Guinea during the West African Ebola epidemic.

BACKGROUND: Malaria case management in the context of the 2014-2016 West African Ebola virus disease (EVD) epidemic was complicated by a similar initial clinical presentation of the two diseases. In September 2014, the World Health Organization (WHO) released recommendations titled, "Guidance on temporary malaria control measures in Ebola-affected countries", which aimed at reducing the risk of EVD transmission and improving malaria outcomes. This guidance recommended malaria diagnostic testing of fever cases only if adequate personal protective equipment (PPE) was available, defined as examination gloves, face shield, disposable gown, boots, and head cover; otherwise presumptive anti-malarial treatment was recommended. The extent to which health workers adhered to these guidelines in affected countries has not been assessed. METHODS: A cross-sectional survey was conducted in 118 health units in Guinea in November 2014 to produce a representative and probabilistic sample of health facilities and patients. Adherence to the EVD-specific malaria case management guidelines during the height of the EVD epidemic was assessed. Associations between case management practices and possible determinants were calculated using multivariate logistic regression, controlling for expected confounders and the complex sample design. RESULTS: Most (78%) facilities reported availability of examination gloves, but adequate PPE was available at only 27% of facilities. Only 28% of febrile patients received correct malaria case management per the WHO temporary malaria case management guidelines. The most common error was diagnostic testing in the absence of adequate PPE (45% of febrile patients), followed by no presumptive treatment in the absence of adequate PPE (14%). Having had a report of an EVD case at a health facility and health worker-reported participation in EVD-specific malaria trainings were associated with lower odds of diagnostic testing and higher odds of presumptive treatment. CONCLUSIONS: Adherence to guidance on malaria case management in EVD-affected countries was low at the height of the EVD epidemic in Guinea, and there was substantial malaria diagnostic testing in the absence of adequate PPE, which could have contributed to increased EVD transmission in the healthcare setting. Conversely, low presumptive treatment when diagnostic tests were not performed may have led to additional morbidity and mortality among malaria positive patients. National malaria control programs may consider preparing contingency plans for future implementation of temporary changes to malaria case management guidelines to facilitate uptake by health workers. Additional training on standard and transmission-based precautions should help health workers understand how to protect themselves in the face of emerging and unknown pathogens.

Ebola Response Impact on Public Health Programs, West Africa, 2014-2017.

Events such as the 2014-2015 West Africa epidemic of Ebola virus disease highlight the importance of the capacity to detect and respond to public health threats. We describe capacity-building efforts during and after the Ebola epidemic in Liberia, Sierra Leone, and Guinea and public health progress that was made as a result of the Ebola response in 4 key areas: emergency response, laboratory capacity, surveillance, and workforce development. We further highlight ways in which capacity-building efforts such as those used in West Africa can be accelerated after a public health crisis to improve preparedness for future events.

Ebola Virus RNA in Semen from an HIV-Positive Survivor of Ebola.

Ebola virus is known to persist in semen of male survivors of Ebola virus disease (EVD). However, maximum duration of, or risk factors for, virus persistence are unknown. We report an EVD survivor with preexisting HIV infection, whose semen was positive for Ebola virus RNA 565 days after recovery from EVD.

Knowledge, Attitudes, and Practices Related to Ebola Virus Disease at the End of a National Epidemic - Guinea, August 2015.

Health communication and social mobilization efforts to improve the public's knowledge, attitudes, and practices (KAP) regarding Ebola virus disease (Ebola) were important in controlling the 2014-2016 Ebola epidemic in Guinea (1), which resulted in 3,814 reported Ebola cases and 2,544 deaths.* Most Ebola cases in Guinea resulted from the washing and touching of persons and corpses infected with Ebola without adequate infection control precautions at home, at funerals, and in health facilities (2,3). As the 18-month epidemic waned in August 2015, Ebola KAP were assessed in a survey among residents of Guinea recruited through multistage cluster sampling procedures in the nation's eight administrative regions (Boké, Conakry, Faranah, Kankan, Kindia, Labé, Mamou, and Nzérékoré). Nearly all participants (92%) were aware of Ebola prevention measures, but 27% believed that Ebola could be transmitted by ambient air, and 49% believed they could protect themselves from Ebola by avoiding mosquito bites. Of the participants, 95% reported taking actions to avoid getting Ebola, especially more frequent handwashing (93%). Nearly all participants (91%) indicated they would send relatives with suspected Ebola to Ebola treatment centers, and 89% said they would engage special Ebola burial teams to remove corpses with suspected Ebola from homes. Of the participants, 66% said they would prefer to observe an Ebola-affected corpse from a safe distance at burials rather than practice traditional funeral rites involving corpse contact. The findings were used to guide the ongoing epidemic response and recovery efforts, including health communication, social mobilization, and planning, to prevent and respond to future outbreaks or sporadic cases of Ebola.

Seroprevalence of Herpes Simplex Virus type-2 (HSV-2) among pregnant women who participated in a national HIV surveillance activity in Haiti.

BACKGROUND: Herpes simplex virus type 2 (HSV-2), one the most common causes of genital ulcers, appears to increase both the risk of HIV acquisition and HIV transmission. HSV-2/HIV co-infection among pregnant women may increase the risk of perinatal transmission of HIV. This study describes rates of HSV-2 among pregnant women in Haiti and HSV-2 test performance in this population. METHODS: Unlinked residual serum specimens from the 2012 National HIV and Syphilis Sentinel Surveillance Survey among pregnant women in Haiti were tested using two commercial kits (Focus HerpeSelect, Kalon) for HSV-2 antibodies. We evaluated rates of HSV-2 seropositivity and HSV-2/HIV co-infection, associations between HSV-2 and demographic characteristics using multivariable Cox proportional hazards modeling, and HSV-2 test performance in this population. RESULTS: Serum samples from 1000 pregnant women (all 164 HIV positive and 836 random HIV negative) were selected. The overall weighted prevalence of HSV-2 was 31.4% (95% CI: 27.7-35.4) and the prevalence of HIV-positivity among HSV-2 positive pregnant women was five times higher than the prevalence among HSV-2 negative women (4.8% [95% CI: 3.9-6.0] vs. 0.9% [95% CI: 0.6-1.3], respectively). Factors significantly associated with HSV-2 positivity were HIV-positivity (PR: 2.27 [95% CI: 1.94-2.65]) and older age (PRs: 1.41 [95% CI: 1.05-1.91] for 20-24 years, 1.71 [95% CI:1.13-2.60] for 30-34 years, and 1.55 [95% CI: 1.10-2.19] for 35 years or greater]), while rural residence was negatively associated with HSV-2 positivity (PR 0.83 [95% CI: 0.69-1.00]), after controlling for other covariables. For this study a conservative Focus index cutoff of 3.5 was used, but among samples with a Focus index value ≥2.5, 98.4% had positive Kalon tests. CONCLUSION: The prevalence of HSV-2 is relatively high among pregnant women in Haiti. Public health interventions to increase access to HSV-2 screening in antenatal services are warranted.

Secondary Infections with Ebola Virus in Rural Communities, Liberia and Guinea, 2014-2015.

Persons who died of Ebola virus disease at home in rural communities in Liberia and Guinea resulted in more secondary infections than persons admitted to Ebola treatment units. Intensified monitoring of contacts of persons who died of this disease in the community is an evidence-based approach to reduce virus transmission in rural communities.

The role of the law in reducing tuberculosis transmission in Botswana, South Africa and Zambia.

OBJECTIVE: To determine whether laws and regulations in Botswana, South Africa and Zambia - three countries with a high tuberculosis and HIV infection burden - address elements of the World Health Organization (WHO) policy on tuberculosis infection control. METHODS: An online desk review of laws and regulations that address six selected elements of the WHO policy on tuberculosis infection control in the three countries was conducted in November 2015 using publicly available domestic legal databases. The six elements covered: (i) national policy and legal framework; (ii) health facility design, construction and use; (iii) tuberculosis disease surveillance among health workers; (iv) patients' and health workers' rights; (v) monitoring of infection control measures; and (vi) relevant research. FINDINGS: The six elements were found to be adequately addressed in the three countries' laws and regulations. In all three, tuberculosis case-reporting is required, as is tuberculosis surveillance among health workers. Each country's legal and regulatory framework also addresses the need to respect individuals' rights and privacy while safeguarding public health. These laws and regulations create a strong foundation for tuberculosis infection control. Although the legal and regulatory frameworks thoroughly address tuberculosis infection control, their dissemination, implementation and enforcement were not assessed, nor was their impact on public health. CONCLUSION: Laws and regulations in Botswana, South Africa and Zambia address all six selected elements of the WHO policy on tuberculosis infection control. However, the lack of data on their implementation is a limitation. Future research should assess the implementation and public health impact of laws and regulations.