Time trends in social contacts of individuals according to comorbidity and vaccination status, before and during the COVID-19 pandemic.

BACKGROUND: As we are confronted with more transmissible/severe variants with immune escape and the waning of vaccine efficacy, it is particularly relevant to understand how the social contacts of individuals at greater risk of COVID-19 complications evolved over time. We described time trends in social contacts of individuals according to comorbidity and vaccination status before and during the first three waves of the COVID-19 pandemic in Quebec, Canada. METHODS: We used data from CONNECT, a repeated cross-sectional population-based survey of social contacts conducted before (2018/2019) and during the pandemic (April 2020 to July 2021). We recruited non-institutionalized adults from Quebec, Canada, by random digit dialling. We used a self-administered web-based questionnaire to measure the number of social contacts of participants (two-way conversation at a distance ≤2 m or a physical contact, irrespective of masking). We compared the mean number of contacts/day according to the comorbidity status of participants (pre-existing medical conditions with symptoms/medication in the past 12 months) and 1-dose vaccination status during the third wave. All analyses were performed using weighted generalized linear models with a Poisson distribution and robust variance. RESULTS: A total of 1441 and 5185 participants with and without comorbidities, respectively, were included in the analyses. Contacts significantly decreased from a mean of 6.1 (95%CI 4.9-7.3) before the pandemic to 3.2 (95%CI 2.5-3.9) during the first wave among individuals with comorbidities and from 8.1 (95%CI 7.3-9.0) to 2.7 (95%CI 2.2-3.2) among individuals without comorbidities. Individuals with comorbidities maintained fewer contacts than those without comorbidities in the second wave, with a significant difference before the Christmas 2020/2021 holidays (2.9 (95%CI 2.5-3.2) vs 3.9 (95%CI 3.5-4.3); P<0.001). During the third wave, contacts were similar for individuals with (4.1, 95%CI 3.4-4.7) and without comorbidities (4.5, 95%CI 4.1-4.9; P=0.27). This could be partly explained by individuals with comorbidities vaccinated with their first dose who increased their contacts to the level of those without comorbidities. CONCLUSIONS: It will be important to closely monitor COVID-19-related outcomes and social contacts by comorbidity and vaccination status to inform targeted or population-based interventions (e.g., booster doses of the vaccine).

The effect of mandatory COVID-19 certificates on vaccine uptake: synthetic-control modelling of six countries.

BACKGROUND: Mandatory COVID-19 certification (showing vaccination, recent negative test, or proof of recovery) has been introduced in some countries. We aimed to investigate the effect of certification on vaccine uptake. METHODS: We designed a synthetic control model comparing six countries (Denmark, Israel, Italy, France, Germany, and Switzerland) that introduced certification (April-August, 2021), with 19 control countries. Using daily data on cases, deaths, vaccinations, and country-specific information, we produced a counterfactual trend estimating what might have happened in similar circumstances if certificates were not introduced. The main outcome was daily COVID-19 vaccine doses. FINDINGS: COVID-19 certification led to increased vaccinations 20 days before implementation in anticipation, with a lasting effect up to 40 days after. Countries with pre-intervention uptake that was below average had a more pronounced increase in daily vaccinations compared with those where uptake was already average or higher. In France, doses exceeded 55 672 (95% CI 49 668-73 707) vaccines per million population or, in absolute terms, 3 761 440 (3 355 761-4 979 952) doses before mandatory certification and 72 151 (37 940-114 140) per million population after certification (4 874 857 [2 563 396-7 711 769] doses). We found no effect in countries that already had average uptake (Germany), or an unclear effect when certificates were introduced during a period of limited vaccine supply (Denmark). Increase in uptake was highest for people younger than 30 years after the introduction of certification. Access restrictions linked to certain settings (nightclubs and events with >1000 people) were associated with increased uptake in those younger than 20 years. When certification was extended to broader settings, uptake remained high in the youngest group, but increases were also observed in those aged 30-49 years. INTERPRETATION: Mandatory COVID-19 certification could increase vaccine uptake, but interpretation and transferability of findings need to be considered in the context of pre-existing levels of vaccine uptake and hesitancy, eligibility changes, and the pandemic trajectory. FUNDING: Leverhulme Trust and European Research Council.

Vaccine Coverage Across the Life Course in Michigan During the COVID-19 Pandemic: January‒September 2020.

Objectives. To assess the impact of the COVID-19 pandemic on immunization services across the life course. Methods. In this retrospective study, we used Michigan immunization registry data from 2018 through September 2020 to assess the number of vaccine doses administered, number of sites providing immunization services to the Vaccines for Children population, provider location types that administer adult vaccines, and vaccination coverage for children. Results. Of 12 004 384 individual vaccine doses assessed, 48.6%, 15.6%, and 35.8% were administered to children (aged 0-8 years), adolescents (aged 9-18 years), and adults (aged 19‒105 years), respectively. Doses administered overall decreased beginning in February 2020, with peak declines observed in April 2020 (63.3%). Overall decreases in adult doses were observed in all settings except obstetrics and gynecology provider offices and pharmacies. Local health departments reported a 66.4% decrease in doses reported. For children, the total number of sites administering pediatric vaccines decreased while childhood vaccination coverage decreased 4.4% overall and 5.8% in Medicaid-enrolled children. Conclusions. The critical challenge is to return to prepandemic levels of vaccine doses administered as well as to catch up individuals for vaccinations missed. (Am J Public Health. 2021;111(11):2027-2035. https://doi.org/10.2105/AJPH.2021.306474).

Measles in Vaccinated People: Epidemiology and Challenges in Surveillance and Diagnosis in the Post-Elimination Phase. Spain, 2014-2020.

The MMR vaccination program was introduced in Spain in 1981. Consistently high vaccination coverage has led to Spain being declared free of endemic measles transmission since 2014. A few imported and import-related cases were reported during the post-elimination phase (2014 to 2020), with very low incidence: three cases per million of inhabitants a year, 70% in adults. In the post-elimination phase an increasing proportion of measles appeared in two-dose vaccinated individuals (up to 14%), posing a challenge to surveillance and laboratory investigations. Severity and clinical presentation were milder among the vaccinated. The IgM response varied and the viral load decreased, making the virus more difficult to detect. A valid set of samples (serum, urine and throat swab) is strongly recommended for accurate case classification. One third of measles in fully vaccinated people was contracted in healthcare settings, mainly in doctors and nurses, consistent with the important role of high intensity exposure in measles breakthrough cases. Surveillance protocols and laboratory algorithms should be adapted in advanced elimination settings. Reinforcing the immunity of people working in high exposure environments, such as healthcare settings, and implementing additional infection control measures, such as masking and social distancing, are becoming crucial for the global aim of measles eradication.

Changes in COVID-19 vaccination receipt and intention to vaccinate by socioeconomic characteristics and geographic area, United States, January 6 - March 29, 2021.

INTRODUCTION: Previous studies suggested that almost one-third of U.S. adults did not plan to get a COVID-19 vaccine once it is available to them. The purpose of this study was to examine changes in vaccine intentions and attitudes by sociodemographic characteristics and geographic areas, factors associated with vaccination intent, and reasons for non-vaccination among a nationally representative sample of U.S. adults. METHODS: Data from six waves of the Household Pulse Survey (6 January - 29 March 2021) were analyzed. Differences between January and March were assessed using t-tests. Factors associated with vaccination intent were examined in multivariable logistic regression models. RESULTS: From early January to late March, vaccination receipt of ≥1 dose of the COVID-19 vaccine or intention to definitely get vaccinated increased from 54.7 to 72.3%; however, disparities in vaccination intent continued to exist by age group, race/ethnic groups, and socioeconomic characteristics. Vaccine receipt and the intent were the lowest for region 4 (southeastern U.S.) throughout this period. Adults who had a previous COVID-19 diagnosis or were unsure if they have had COVID-19 were less likely to intend to get vaccinated [prevalence ratio = 0.92 (95%CI: 0.90-0.93) and 0.80 (95%CI: 0.74-0.85), respectively]. The belief that a vaccine is not needed increased by more than five percentage points from early January to late March. CONCLUSION: Intent to definitely get a COVID-19 vaccine increased by almost 18 percentage points from early January to late March; however, younger adults, adults who are non-Hispanic Black or other races, adults of lower socioeconomic status, and adults living in the southeastern U.S. region (Region 4) continue to have higher coverage gaps and levels of vaccine hesitancy. Emphasizing the importance of vaccination among all populations, and removing barriers to vaccines, may lead to a reduction of COVID-19 incidence and bring an end to the pandemic.KEY MESSAGESReceipt of ≥1 dose of the COVID-19 vaccine and intent to probably or definitely get vaccinated increased from early January to late March; however, disparities in vaccine intent continued to exist by age group, race/ethnic groups, and socioeconomic characteristics.Vaccine receipt and the intent were the lowest for region 4 (southeastern U.S.) compared to other regions during this period.Adults who had a previous COVID-19 diagnosis or were unsure if they have had COVID-19 were less likely to intend to get vaccinated; overall, the belief that a vaccine is not needed to be increased by more than 5% points from early January to late March.[Formula: see text].

Impact of the SARS-CoV-2 pandemic on the administration of vaccines as per the national immunization schedule in children younger than 2 years. / Impacto de la pandemia por SARS-CoV-2 en la administración de vacunas del Calendario Nacional de Inmunizaciones en menores de 2 años.

INTRODUCTION: The reduction in the number of visits to health care centers since the onset of the SARS-CoV-2 pandemic may affect mandatory vaccination. OBJECTIVE: To assess the impact of the SARS-CoV-2 pandemic on the administration of the pentavalent and the measles, mumps, and rubella (MMR) vaccines to children younger than 2 years at the vaccination center of a children's hospital in the Autonomous City of Buenos Aires. METHOD: Cross-sectional study using the vaccination center's digital records from January to May 2019 and 2020. Results. In the second fortnight of March 2020, vaccinations dropped by 64.2 %. When examining the first dose of the pentavalent and MMR vaccines, such reduction was 74.9 % and 55.1 %, respectively. CONCLUSION: As of the second fortnight of March 2020, vaccinations dropped by 64.2 % compared to the same period of the previous year.

Introducción. El menor número de consultas a los centros de atención desde el comienzo de la pandemia por SARS-CoV-2 podría afectar la vacunación obligatoria. Objetivo. Evaluar el impacto de la pandemia por SARS-CoV-2 en la administración de vacunas pentavalente y triple viral a niños menores de 2 años en el vacunatorio de un hospital pediátrico de la Ciudad de Buenos Aires. Método. Estudio transversal, que utilizó registros informatizados del vacunatorio, de enero a mayo de 2019 y 2020. Resultados. Desde la segunda quincena de marzo de 2020, se observó un 64,2 % de disminución en la aplicación de vacunas. Al examinar la primera dosis de pentavalente y triple viral, la reducción fue del 74,9 % y del 55,1 %, respectivamente. Conclusión. A partir de la segunda quincena de marzo de 2020, se observó una disminución del 64,2 % en las vacunas aplicadas respecto del mismo período en el año anterior.

A global database of COVID-19 vaccinations.

An effective rollout of vaccinations against COVID-19 offers the most promising prospect of bringing the pandemic to an end. We present the Our World in Data COVID-19 vaccination dataset, a global public dataset that tracks the scale and rate of the vaccine rollout across the world. This dataset is updated regularly and includes data on the total number of vaccinations administered, first and second doses administered, daily vaccination rates and population-adjusted coverage for all countries for which data are available (169 countries as of 7 April 2021). It will be maintained as the global vaccination campaign continues to progress. This resource aids policymakers and researchers in understanding the rate of current and potential vaccine rollout; the interactions with non-vaccination policy responses; the potential impact of vaccinations on pandemic outcomes such as transmission, morbidity and mortality; and global inequalities in vaccine access.

Vaccination strategies for measles control and elimination: time to strengthen local initiatives.

BACKGROUND: Through a combination of strong routine immunization (RI), strategic supplemental immunization activities (SIA) and robust surveillance, numerous countries have been able to approach or achieve measles elimination. The fragility of these achievements has been shown, however, by the resurgence of measles since 2016. We describe trends in routine measles vaccine coverage at national and district level, SIA performance and demographic changes in the three regions with the highest measles burden. FINDINGS: WHO-UNICEF estimates of immunization coverage show that global coverage of the first dose of measles vaccine has stabilized at 85% from 2015 to 19. In 2000, 17 countries in the WHO African and Eastern Mediterranean regions had measles vaccine coverage below 50%, and although all increased coverage by 2019, at a median of 60%, it remained far below levels needed for elimination. Geospatial estimates show many low coverage districts across Africa and much of the Eastern Mediterranean and southeast Asian regions. A large proportion of children unvaccinated for MCV live in conflict-affected areas with remote rural areas and some urban areas also at risk. Countries with low RI coverage use SIAs frequently, yet the ideal timing and target age range for SIAs vary within countries, and the impact of SIAs has often been mitigated by delays or disruptions. SIAs have not been sufficient to achieve or sustain measles elimination in the countries with weakest routine systems. Demographic changes also affect measles transmission, and their variation between and within countries should be incorporated into strategic planning. CONCLUSIONS: Rebuilding services after the COVID-19 pandemic provides a need and an opportunity to increase community engagement in planning and monitoring services. A broader suite of interventions is needed beyond SIAs. Improved methods for tracking coverage at the individual and community level are needed together with enhanced surveillance. Decision-making needs to be decentralized to develop locally-driven, sustainable strategies for measles control and elimination.

Pandemic and vaccine coverage: challenges of returning to schools.

Since March 2020, Brazil has faced the pandemic of the coronavirus disease 2019 (Covid-19), which has severely modified the way in which the population lives and uses health services. As such, face-to-face attendance has dropped dramatically, even for child vaccination, due to measures of social distancing to mitigate the transmission of the virus. Several countries have recorded a substantial drop in vaccination coverage in children, especially of those under two years of age. In Brazil, administrative data indicate the impact of the covid-19 pandemic on this downward trend, which was already an important challenge of the National Immunization Program in recent years. Many children will be susceptible to immunopreventable diseases, which reinforces the need to assess the vaccine status of schoolchildren before returning to face-to-face classes.

Vaccines and routine immunization strategies during the COVID-19 pandemic.

Severe acute respiratory syndrome coronavirus 2 related disease (COVID-19) is now responsible for one of the most challenging and concerning pandemics. By August 2020, there were almost 20 million confirmed cases worldwide and well over half-million deaths. Since there is still no effective treatment or vaccine, non-pharmaceutical interventions have been implemented in an attempt to contain the spread of the virus. During times of quarantine, immunization practices in all age groups, especially routine childhood vaccines, have also been interrupted, delayed, re-organized, or completely suspended. Numerous high-income as well as low- and middle-income countries are now experiencing a rapid decline in childhood immunization coverage rates. We will, inevitably, see serious consequences related to suboptimal control of vaccine-preventable diseases (VPDs) in children concurrent with or following the pandemic. Routine pediatric immunizations of individual children at clinics, mass vaccination campaigns, and surveillance for VPDs must continue as much as possible during pandemic.