Herd Immunity against Severe Acute Respiratory Syndrome Coronavirus 2 Infection in 10 Communities, Qatar

We investigated what proportion of the population acquired severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and whether the herd immunity threshold has been reached in 10 communities in Qatar. The study included 4,970 participants during June 21-September 9, 2020. Antibodies against SARS-CoV-2 were detected by using an electrochemiluminescence immunoassay. Seropositivity ranged from 54.9% (95% CI 50.2%-59.4%) to 83.8% (95% CI 79.1%-87.7%) across communities and showed a pooled mean of 66.1% (95% CI 61.5%-70.6%). A range of other epidemiologic measures indicated that active infection is rare, with limited if any sustainable infection transmission for clusters to occur. Only 5 infections were ever severe and 1 was critical in these young communities; infection severity rate of 0.2% (95% CI 0.1%-0.4%). Specific communities in Qatar have or nearly reached herd immunity for SARS-CoV-2 infection: 65%-70% of the population has been infected.

Transmission of Chikungunya Virus in an Urban Slum, Brazil

After a chikungunya outbreak in Salvador, Brazil, we performed a cross-sectional, community-based study of 1,776 inhabitants to determine chikungunya virus (CHIKV) seroprevalence, identify factors associated with exposure, and estimate the symptomatic infection rate. From November 2016 through February 2017, we collected sociodemographic and clinical data by interview and tested serum samples for CHIKV IgG. CHIKV seroprevalence was 11.8% (95% CI 9.8%–13.7%), and 15.3% of seropositive persons reported an episode of fever and arthralgia. Infections were independently and positively associated with residences served by unpaved streets, a presumptive clinical diagnosis of chikungunya, and recall of an episode of fever with arthralgia in 2015–2016. Our findings indicate that the chikungunya outbreak in Salvador may not have conferred sufficient herd immunity to preclude epidemics in the near future. The unusually low frequency of symptomatic disease points to a need for further longitudinal studies to better investigate these findings.

'Keeping the kids at home' can limit the persistence of contagious pathogens in social animals

Social networks are considered to be 'highly modular' when individuals within one module are more connected to each other than they are to individuals in other modules. It is currently unclear how highly modular social networks influence the persistence of contagious pathogens that generate lifelong immunity in their hosts when between-group interactions are age dependent. This trait occurs in social species with communal nurseries, where juveniles are reared together for a substantial period in burrows or similar forms of containment and are thus in isolation from contact with individuals in other social groups. Our main objective was to determine whether, and to what extent, such age-dependent patterns of between-group interactions consistently increased the fade-out probability of contagious pathogens that generate lifelong immunity in their hosts. We hypothesised that in populations of species where juveniles are raised in communal nurseries, a high proportion of recovered adults in a group would form a 'protective barrier' around susceptible juveniles against pathogen transmission, thereby increasing the probability of epidemic fade-out in the population. To test this idea, we implemented a spatially implicit individual-based susceptible-infected-recovered (SIR) model for a large range of generic host and pathogen traits. Our results indicated that (a) the probability of epidemic fade-out was consistently higher in populations with communal nurseries, especially for highly contagious pathogens (high basic reproduction number, R₀ ) and (b) communal nurseries can counteract the cost of group living in terms of infection risk to a greater extent than variation in other traits. We discuss our findings in relation to herd immunity and outline the importance of considering the network structure of a given host population before implementing management measures such as vaccinations, since interventions focused on individuals with high between-group contact should be particularly effective for controlling pathogen spread in hosts with communal nurseries.

COVID-19 vaccine hesitancy: a survey in a population highly compliant to common vaccinations

Vaccination is a key protective factor against COVID-19. Some vaccines have already received emergency authorization from Health Agencies, but growing skepticism and vaccine hesitancy will probably affect COVID-19 vaccination campaigns. In the attempt to shed light on this issue, we conducted an online survey in a population of parents referring to 4 pediatric practices in Naples, Italy in whom we evaluated potential vaccine acceptability in relation to socio-demographic characteristics, perception of personal health and of the impact of COVID-19, and attitudes toward general vaccination practices. Vaccination rates were analyzed also in the corresponding pediatric population.Almost 27% of participants declared they were in favor of vaccinations, and in fact real life vaccination rates in children exceeded the national mean. Only 26.5% of respondents declared they would receive COVID-19 vaccine. Vaccine refusal was attributed to safety concerns in 76% of parents. Specific vaccine attributes further reduced the acceptance rate. Female gender, younger age and lower education level were associated with non-adherence to vaccination. Among extrinsic factors of COVID-19 vaccination, only information from National Health Authorities was significantly associated to vaccine acceptance.The rate of potential COVID-19 vaccine acceptability was very poor in our population of parents. Vaccine hesitancy was mainly due to safety concerns. Demographic and educational factors were correlated to vaccine acceptability. Health education and communication strategies are needed to achieve large-scale vaccine acceptability and finally herd immunity.

Combating COVID-19 pandemic in India: Demystifying the concept of herd immunity

The concept of Herd immunity is a key factor for epidemic control. According to it only a proportion of entire population needs to be immune either via natural infection or vaccination. The idea of herd immunity via natural infection rather than vaccination is a bit controversial, as it is not clear how long will the antibodies last, and whether re-infection or re-activation of the virus can occur after the antibodies starts weaning from the body. It has been suggested that coronavirus will likely become similar to a seasonal flu once the herd immunity is attained. Till then, it will continue causing outbreaks year-round and there could be multiple waves of virus transmission before achieving herd immunity. Therefore, the public needs to learn to live with it, and continue practising the best prevention measures, including wearing of masks, physical distancing, hand hygiene, and avoidance of gathering.

Population Impact of Girls-Only Human Papillomavirus 16/18 Vaccination in The Netherlands: Cross-Protective and Second-Order Herd Effects

Background

Human papillomavirus (HPV) vaccination programs achieve substantial population-level impact, with effects extending beyond protection of vaccinated individuals. We assessed trends in HPV prevalence up to 8 years postvaccination among men and women in the Netherlands, where bivalent HPV vaccination, targeting HPV types 16/18, has been offered to (pre)adolescent girls since 2009 with moderate vaccination coverage.

Methods

We used data from the PASSYON study, a survey initiated in 2009 (prevaccination) and repeated biennially among 16- to 24-year-old visitors of sexual health centers. We studied genital HPV positivity from 2009 to 2017 among women, heterosexual men, and unvaccinated women using Poisson generalized estimating equation models, adjusted for individual- and population-level confounders. Trends were studied for 25 HPV types detected by the SPF10-LiPA25 platform.

Results

A total of 6354 women (64.7% self-reported unvaccinated) and 2414 heterosexual men were included. Percentual declines in vaccine types HPV-16/18 were observed for all women (12.6% per year [95% confidence interval {CI}, 10.6–14.5]), heterosexual men (13.0% per year [95% CI, 8.3–17.5]), and unvaccinated women (5.4% per year [95% CI, 2.9–7.8]). We observed significant declines in HPV-31 (all women and heterosexual men), HPV-45 (all women), and in all high-risk HPV types pooled (all women and heterosexual men). Significant increases were observed for HPV-56 (all women) and HPV-52 (unvaccinated women).

Conclusions

Our results provide evidence for first-order herd effects among heterosexual men against HPV-16/18 and cross-protective types. Additionally, we show second-order herd effects against vaccine types among unvaccinated women. These results are promising regarding population-level and clinical impact of girls-only bivalent HPV vaccination in a country with moderate vaccine uptake.

Humor and Fear-Two Sides of the Same Coin?: Experimental Evidence on Humor Appeals in Health Communication Related to Childhood Vaccination

Until now, health communication has largely failed to debunk fears and caveats related to vaccination. This study aims to investigate the effects of different text types used in health communication in an experimental study design. A neutrally formulated text was compared to a humorous text using the formula of a fairytale. Overall, the study indicates no additional value in using the humorous format as an innovative and target-group-oriented approach to inform readers about scientific evidence related to vaccination. Although the effects of the two text types do not differ, the credibility of the neutrally formulated text was much more likely to be judged as high. This indicates that the perception of credibility is not the only criterion in health communication leading to knowledge gains and changes in health-related attitudes and behaviors.

COVID-19 Vaccines: A Review of the Safety and Efficacy of Current Clinical Trials

Various strategies have been designed to contain the COVID-19 pandemic. Among them, vaccine development is high on the agenda in spite of the unknown duration of the protection time. Various vaccines have been under clinical trials with promising results in different countries. The protective efficacy and the short-term and long-term side effects of the vaccines are of major concern. Therefore, comparing the protective efficacy and risks of vaccination is essential for the global control of COVID-19 through herd immunity. This study reviews the most recent data of 12 vaccines to evaluate their efficacy, safety profile and usage in various populations.

Considering Needle Phobia among Adult Patients During Mass COVID-19 Vaccinations

As mass vaccination is underway to combat the COVID-19 pandemic and achieve herd immunity, healthcare professionals need to recognize the fear and phobia of needles among their patients. Approximately 11.5 to 66 million U.S. adults may suffer from this condition. This population often avoids seeking medical care including vaccinations. The exact number of people suffering from this phobia is unknown, and the potential years of life lost in the American health care system cannot be estimated accurately. The resistance to vaccinations among this population may delay achieving herd immunity to end this current pandemic. An overview of needle phobia, vaccinations, and current treatments are explored. The use of telemedicine could prove critical for reaching this population as well as those who are hesitant about vaccinations. Providing education to healthcare providers to identify and manage these patients during the pandemic is necessary.

SARS-CoV-2 IgG Antibodies Seroprevalence and Sera Neutralizing Activity in MEXICO: A National Cross-Sectional Study during 2020

Until recently, the incidence of COVID-19 was primarily estimated using molecular diagnostic methods. However, the number of cases is vastly underreported using these methods. Seroprevalence studies estimate cumulative infection incidences and allow monitoring of transmission dynamics, and the presence of neutralizing antibodies in the population. In February 2020, the Mexican Social Security Institute began conducting anonymous unrelated sampling of residual sera from specimens across the country, excluding patients with fever within the previous two weeks and/or patients with an acute respiratory infection. Sampling was carried out weekly and began 17 days before Mexico's first officially confirmed case. The 24,273 sera obtained were analyzed by chemiluminescent-linked immunosorbent assay (CLIA) IgG S1/S2 and, later, positive cases using this technique were also analyzed to determine the rate of neutralization using the enzyme-linked immunosorbent assay (ELISA). We identified 40 CLIA IgG positive cases before the first official report of SARS-CoV-2 infection in Mexico. The national seroprevalence was 3.5% in February and 33.5% in December. Neutralizing activity among IgG positives patients during overall study period was 86.1%. The extent of the SARS-CoV-2 infection in Mexico is 21 times higher than that reported by molecular techniques. Although the general population is still far from achieving herd immunity, epidemiological indicators should be re-estimated based on serological studies of this type.

Critical interpretative synthesis of herd immunity for COVID-19 pandemic

Introduction:

Countries globally are evaluating the concept of herd immunity and its critical role in the control of pandemic. The current paper attempts to conduct a critical interpretative synthesis (CIS) on the role of herd immunity in current COVID-19 pandemic.

Methods:

CIS is tool for developing theoretical framework using interpretation drawn from relevant empirical and non-empirical sources. This review is done by formulating review question for literature search. Purposive sampling of literature was done followed by reciprocal translational analysis of extracted data.

Results:

Herd immunity is indirect protection from a contagious infectious disease when a population is immune either through vaccination or natural immunity developed through previous infection. The reproduction number for COVID-19 in India was found to be 2.56 and herd immunity threshold as 61%.

Discussion:

Exposing 71% young population in India to the SARS-CoV-2 infection can achieve herd immunity but with high morbidity as well as mortality. Vaccine are under process. Feco-oral transmission and reinfection of COVID 19 are major factors to develop or break the circle of herd immunity in community. “Immunity passport” can give false sense of security. Surveillance and seroprevalence studies assess immunity status, gradual exposure of infection to younger population and collaborative partnerships on organizations are few strategies to acquire herd immunity.

Conclusion:

Herd immunity is a measure for prevention and control of COVID-19 pandemic against the backdrop of mortality and morbidity. Vaccine can be boon but if herd immunity is to be acquired by natural infection then preparedness is necessary.

Incidence and Death Rates from COVID-19 Are Not Always Coupled: An Analysis of Temporal Data on Local, Federal, and National Levels

SARS-CoV-2 has caused a deadly pandemic worldwide, placing a burden on local health care systems and economies. Infection rates with SARS-CoV-2 and the related mortality of COVID-19 are not equal among countries or even neighboring regions. Based on data from official German health authorities since the beginning of the pandemic, we developed a case-fatality prediction model that correctly predicts COVID-19-related death rates based on local geographical developments of infection rates in Germany, Bavaria, and a local community district city within Upper Bavaria. Our data point towards the proposal that local individual infection thresholds, when reached, could lead to increasing mortality. Restrictive measures to minimize the spread of the virus could be applied locally based on the risk of reaching the individual threshold. Being able to predict the necessity for increasing hospitalization of COVID-19 patients could help local health care authorities to prepare for increasing patient numbers.

Demystifying R Naught: Understanding What Does it Hide?

Since the onset of the pandemic in Wuhan city, China, forecasting and projections of the pandemic are the areas of interest for the investigators, and the basic reproduction rate R0 always stayed the favorite tool. The basic reproduction number (R0) is either ratio or rate or the basic reproductive rate. This dimensionless number was calculated in the past to describe the contagiousness or transmissibility of infectious agents for many communicable diseases. Its importance in the context of COVID-19 is not less, it tells us about the public health measures to be undertaken for disease prevention, and how the transmission of COVID-19 will be affected or eliminated. R0 is affected by several biological, sociobehavioral, and environmental factors which decide agent transmission. R0 is estimated by using complex mathematical models, the results of which are easily distorted, misjudged, and misused. R0 is not a biological constant for an agent or pathogen, it is a rate over time. It can measure the disease severity and also gives an estimate about the herd immunity required for the reversal of epidemic. R0 cannot be altered through vaccination campaigns though it can tell us about the relationship between the population's immune status and epidemic curve. Modeled R0 values are dependent on the model structures and assumptions made. Some R0 values reported in the scientific literature are likely outdated as assumptions are frequently changing in the current pandemic. R0 must be predicted and applied with great caution as this basic metric is far from simple.

Challenges and potential solutions in the development of COVID-19 pandemic control measures

The coronavirus disease 2019 pandemic has become an unprecedented and major health concern all over the world. We discuss potential solutions and feasible strategies to reduce spread of infection and to develop disease control measures.

COVID-19 first anniversary review of cases, hospitalization, and mortality in the UK

Introduction: The first confirmed COVID-19 case in UK dates to 11 January 2020, exhibiting its first peak during April 2020. The country has since been hit by another wave in the winter 2020, almost at the first anniversary of the pandemic.Areas covered: An in-depth analysis of the COVID-19 positive cases in the UK throughout the year, hospitalizations, patients in critical care, and COVID-19 associated deaths.Expert opinion: The COVID-19 associated hospital admission accounts to 15% of total COVID-19 positive cases in November 2020. The percentage of total COVID-19 positive patients in the country died from the disease was under 4% in November 2020. Total deaths in England (all-cause) from June to October 2020 were similar to the historic averages. Age was the single most determinator of COVID-19 associated mortality, 50 years or older accounted for 98% of total COVID deaths. Age distribution of COVID-19 associated deaths in 2020 was similar to all-cause mortality age distribution in 2019. There was no significant improvement in the survival rate of COVID-19 patients receiving critical care. This prompts an urgent need to invest in novel antiviral therapeutics to save the most vulnerable in the society.

Corona vaccine review

Összefoglaló. A SARS-CoV-2 okozta megbetegedés (COVID-19) a cikk megírásáig a világon több mint 82 millió embert érintett, a halálos áldozatok száma 1,8 millió (2,2%). Hazánkban eddig 300 000 feletti esetszámot regisztráltak, a cikk megjelenésének idején már várhatóan több mint 10 000 halottal (3%). Habár a megbetegedésnek oki gyógyszeres terápiája egyelőre nincs, egyes antivirális szerek és a rekonvaleszcens plazma alkalmazása a tapasztalatok szerint csökkentik a vírusterhelést, és ezzel hozzájárulnak a beteg gyógyulásához. Az eddig példa nélküli epidemiológiai rendelkezések nem tudták megállítani, csak lelassítani a betegség terjedését, ezért a megelőzés tűnik az egyetlen, a közeljövőben tömegek számára is elérhető megoldásnak. A jelen cikk nem egy virológiai vagy biotechnológiai szakmunka, sokkal inkább egy összefoglaló házi- és általános orvosok számára, amely ismerteti a jelenleg engedélyezett, illetve a közeljövőben forgalomba kerülő védőoltások előnyeit és hátrányait a COVID-19 tágabb kontextusában. Írásunkban bemutatjuk a leggyakoribb álhíreket, rémhíreket is, valamint ezek cáfolatát is annak érdekében, hogy kollégáink felkészültebben tudják betegeiket informálni, valamint segíteni a vakcináció fontosságával kapcsolatos döntéshozatalt. Egy járvány megfékezésének legkézenfekvőbb módja a társadalmi szintű védettség megvalósítása. A nyájimmunitás kialakulása nélkül nagy valószínűséggel e jelenlegi pandémia sem állítható meg. Amennyiben egyéni és társadalmi szinten is vissza szeretnénk térni a vírus előtti életünkhöz, újra élvezve az akadálytalan áru- és kereskedelmi forgalom jelentette előnyöket, akkor a tömeges oltás tűnik a leghatékonyabb eszköznek ennek eléréséhez. A fertőző betegségek számának és mortalitásának a 20. században tapasztalt jelentős csökkenése egyértelműen a társadalmi szintű átoltottságnak, valamint a higiénés körülmények javulásának köszönhető. Az oltás ugyan önkéntes, de felvételének kérdése pandémiás helyzetben valószínűleg nemcsak egyéni döntés, de társadalmi felelősségvállalás kérdése is. Orv Hetil. 2021; 162(8): 283-292. Summary. Out of more than 82 million people worldwide, 1.8 million (2.2%) succumbed to SARS-CoV-2 disease (COVID-19). In 2020, more than 300 000 cases were registered in Hungary, and by the time of publication of this article, the death toll would probably exceed 10 000 (3%). Currently no causative drug therapy is available, however, observational evidence suggests that certain antivirals and the use of convalescent plasma may change the disease course. The unprecedented, strict epidemiological provisions managed to slow down the spread of the disease though they could not stop it. It seems that prevention remains the only readily available option to beat COVID-19. This is not a virology or biotechnology paper, but an unbiased review for general practitioners, aiming to summarize the advantages/disadvantages of the (emergency) authorized and soon-to-be-launched vaccines in the wider context of COVID-19. We also intended to address and debunk the most common misconceptions, aiming to help both doctors and patients to make a fact-based, informed decision about vaccination. Herd immunity is paramount to combat COVID pandemic. Without population-level vaccination, we are unlikely to regain the quality of life, the freedom of travel and the unrestricted economy/commerce we enjoyed before. It is obvious that the significant reduction in morbity/mortality of infectious diseases in the 20th century was achieved through advancements in vaccinology and improved hygiene. Albeit voluntary, vaccination in a pandemic situation is probably not only an individual decision, but social responsibility as well. Orv Hetil. 2021; 162(8): 283-292.

COVID-19 and immunity: quo vadis?

Understanding the precise nature and durability of protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential in order to gain insight into the pathophysiology of coronavirus disease 2019 (COVID-19) and to develop novel treatment strategies to this disease. Here I succinctly summarize what is currently known and unknown about the immune response during COVID-19 and discuss whether natural infections can lead to herd immunity.

Ethics of Vaccination in Childhood-A Framework Based on the Four Principles of Biomedical Ethics

Although vaccination is recognised as the top public health achievement of the twentieth century, unequivocal consensus about its beneficence does not exist among the general population. In countries with well-established immunisation programmes, vaccines are “victims of their own success”, because low incidences of diseases now prevented with vaccines diminished the experience of their historical burdens. Increasing number of vaccine-hesitant people in recent years threatens, or even effectively disables, herd immunity levels of the population and results in outbreaks of previously already controlled diseases. We aimed to apply a framework for ethical analysis of vaccination in childhood based on the four principles of biomedical ethics (respect for autonomy, nonmaleficence, beneficence and justice) to provide a comprehensive and applicable model on how to address the ethical aspects of vaccination at both individual and societal levels. We suggest finding an “ethical equilibrium”, which means that the degree of respect for parents’ autonomy is not constant, but variable; it shall depend on the level of established herd immunity and it is specific for every society. When the moral obligation of individuals to contribute to herd immunity is not fulfilled, mandatory vaccination policies are ethically justified, because states bear responsibility to protect herd immunity as a common good.

Intake Vaccinations Reduced Signs of Canine Respiratory Disease During an Outbreak at an Animal Shelter

Animal shelters provide an ideal environment for the spread of disease. Dogs are often housed in close quarters with others of unknown vaccine histories, and experience high levels of sustained stress. As a result, Canine Infection Respiratory Disease (CIRD) is often prevalent and difficult to control. The aims of this study were to (1) identify specific pathogens responsible for CIRD in a city shelter in West Texas, USA, and (2) determine whether intake vaccinations decrease proportion of dogs exhibiting signs of CIRD even during an outbreak. A laboratory analysis of conjunctival, pharyngeal, and nasal swabs (n = 15 dogs) and fecal samples (n = 6 kennels) showed prevalence of various CIRD pathogens (e.g., canine adenovirus-2, canine parainfluenza virus, canine distemper virus). All fifteen dogs tested positive for at least one pathogen, with the most prevalent pathogen being Canine Distemper Virus (CDV; n = 12). All of the kennels (n=6) tested positive for Canine Distemper Virus. Health data on dogs (n = 1,258) over the age of 6 weeks were assessed from May to August 2017. Beginning in July, both stray and owner-surrendered dogs were vaccinated with Nobivac^® Canine 1-DAPPv 5 Way and Nobivac^® Intra-Trac^® 3 upon intake, which differed from the previous policy. For each day in the study, we calculated the proportion of dogs in each nasal discharge category, the proportion of dogs observed coughing, and the mean fecal score across all dogs. We conducted a linear regression between the proportion of the shelter vaccinated and the proportion of dogs coughing. At the beginning of the vaccination phase, ~25% of the dogs were coughing. However, as the proportion of the dogs vaccinated increased, the proportion of dogs coughing decreased. There was a significant decrease of 7% of the proportion of dogs coughing when vaccination was at least at 90% compared to when it was <90%. These data suggest that the shelter in this study was experiencing a CIRD outbreak, with CDV being primary pathogen, and that it is possible to substantially reduce illness by implementing a vaccination on intake protocol. The current study provides support for the importance of vaccination in animal shelter welfare.

Lockdowns and the COVID-19 pandemic: What is the endgame?

An overall long-term strategy for managing the coronavirus disease 2019 (COVID-19) pandemic is presented. This strategy will need to be maintained until herd immunity is achieved, hopefully through vaccination rather than natural infection. We suggest that a pure test-trace-isolate strategy is likely not practicable in most countries, and a degree of social distancing, ranging up to full lockdown, is the main public-health tool to mitigate the COVID-19 pandemic. Guided by reliable surveillance data, distancing should be continuously optimised down to the lowest sustainable level that guarantees a low and stable infection rate in order to balance its wide-ranging negative effects on public health. The qualitative mixture of social-distancing measures also needs to be carefully optimised in order to minimise social costs.

Transmission-Blocking Vaccines: Harnessing Herd Immunity for Malaria Elimination

INTRODUCTION

Transmission-blocking vaccines (TBV) prevent community spread of malaria by targeting mosquito sexual stage parasites, a life-cycle bottleneck, and will be used in elimination programs. TBV rely on herd immunity to reduce mosquito infections and thereby new infections in both vaccine recipients and non-recipients, but do not provide protection once an individual receives an infectious mosquito bite which complicates clinical development.

AREAS COVERED

Here, we describe the concept and biology behind TBV, and we provide an update on clinical development of the leading vaccine candidate antigens. Search terms 'malaria vaccine,' 'sexual stages,' 'transmission blocking vaccine,' 'VIMT' and 'SSM-VIMT' were used for PubMed queries to identify relevant literature.

EXPERT OPINION

Candidates targeting P. falciparum zygote surface antigen Pfs25, and its P. vivax orthologue Pvs25, induced functional activity in humans that reduced mosquito infection in surrogate assays, but require increased durability to be useful in the field. Candidates targeting gamete surface antigens Pfs230 and Pfs48/45, respectively, are in or nearing clinical trials. Nanoparticle platforms and adjuvants are being explored to enhance immunogenicity. Efficacy trials require special considerations, such as cluster-randomized designs to measure herd immunity that reduces human and mosquito infection rates, while addressing human and mosquito movements as confounding factors.

Flattening the Curve of COVID-19 Vaccine Rejection-An International Overview

BACKGROUND

If globally implemented, a safe coronavirus disease 2019 (COVID-19) vaccination program will have broad clinical and socioeconomic benefits. However, individuals who anticipate that the coronavirus vaccine will bring life back to normality may be disappointed, due to the emerging antivaccination attitude within the general population.

METHODS

We surveyed a sample of adult Polish citizens (n = 1066), and compared it with the data on international COVID-19 vaccine reluctance.

RESULTS

In 20 national surveys, the vaccine averseness for the anticipated COVID-19 vaccine varied from meager (2-6% China) to very high (43%, Czech Republic, and 44%, Turkey) and in most countries was much higher than regular vaccination reluctance, which varies between 3% (Egypt) and 55% (Russia).

CONCLUSIONS

These results suggest that a 67% herd immunity may be possible only if mandatory preventive vaccination programs start early and are combined with coordinated education efforts supported by legislative power and social campaigns.

The Flu Vaccination May Have a Protective Effect on the Course of COVID-19 in the Pediatric Population: When Does Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Meet Influenza?

Background In the midst of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, a lot more chaos could be anticipated in the flu season due to the coexistence of SARS-CoV-2 and influenza with almost similar epidemiologic and clinical features. Could this become a "twindemic" or "syndemic" if there is any viral interference occurs? We investigated the effect of influenza and pneumococcal vaccines on the disease course of SARS-CoV-2 in the pediatric population and the possibility of viral interference. Material and methods After approval from Institutional Review Board, a retrospective electronic chart review on 20 years and younger SARS-CoV-2 polymerase chain reaction (PCR) positive patients who visited Arkansas Children's Hospital System between February 1 to August 30, 2020, was performed. The clinical data was collected along with influenza and pneumococcal vaccination status of these patients. Results The results showed that viral interference may have played a role in the current flu and coronavirus disease 2019 (COVID-19) twindemic. SARS-CoV-2 and influenza may have significantly affected each other's epidemiological features. Conclusion Understanding the relationship and co-existence of other viruses alongside SARS-CoV-2 and knowing the vaccination status of the host population may help in deploying the right strategies to get the best outcomes.

Toward Achieving a Vaccine-Derived Herd Immunity Threshold for COVID-19 in the U.S

A novel coronavirus emerged in December of 2019 (COVID-19), causing a pandemic that inflicted unprecedented public health and economic burden in all nooks and corners of the world. Although the control of COVID-19 largely focused on the use of basic public health measures (primarily based on using non-pharmaceutical interventions, such as quarantine, isolation, social-distancing, face mask usage, and community lockdowns) initially, three safe and highly-effective vaccines (by AstraZeneca Inc., Moderna Inc., and Pfizer Inc.), were approved for use in humans in December 2020. We present a new mathematical model for assessing the population-level impact of these vaccines on curtailing the burden of COVID-19. The model stratifies the total population into two subgroups, based on whether or not they habitually wear face mask in public. The resulting multigroup model, which takes the form of a deterministic system of nonlinear differential equations, is fitted and parameterized using COVID-19 cumulative mortality data for the third wave of the COVID-19 pandemic in the United States. Conditions for the asymptotic stability of the associated disease-free equilibrium, as well as an expression for the vaccine-derived herd immunity threshold, are rigorously derived. Numerical simulations of the model show that the size of the initial proportion of individuals in the mask-wearing group, together with positive change in behavior from the non-mask wearing group (as well as those in the mask-wearing group, who do not abandon their mask-wearing habit) play a crucial role in effectively curtailing the COVID-19 pandemic in the United States. This study further shows that the prospect of achieving vaccine-derived herd immunity (required for COVID-19 elimination) in the U.S., using the Pfizer or Moderna vaccine, is quite promising. In particular, our study shows that herd immunity can be achieved in the U.S. if at least 60% of the population are fully vaccinated. Furthermore, the prospect of eliminating the pandemic in the U.S. in the year 2021 is significantly enhanced if the vaccination program is complemented with non-pharmaceutical interventions at moderate increased levels of compliance (in relation to their baseline compliance). The study further suggests that, while the waning of natural and vaccine-derived immunity against COVID-19 induces only a marginal increase in the burden and projected time-to-elimination of the pandemic, adding the impacts of therapeutic benefits of the vaccines into the model resulted in a dramatic reduction in the burden and time-to-elimination of the pandemic.