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What do we know about COVID-19 reducing life expectancy?

Life expectancy is the estimated number of years that a person can expect to live based on their current age in a specific place. Life expectancy is often measured in two ways. The first way is called Period Life Expectancy and it is calculated by measuring how frequently people died in a specific group in a specific time and then multiplied to represent an entire population. The second way life expectancy can be measured is through using a Cohort Life Expectancy approach and this is measured by calculating mortality risks throughout the lifetimes of a group of individuals born during the same period of time. Because of advances in medical treatment, before 2020, period life expectancy was increasing in many parts of the world. As a result of deaths that have happened during the COVID-19 pandemic, many experts have said that period life expectancy values will decrease, at least temporarily. While period life expectancy is commonly used to report on population health, it is a projection that cannot account for any future changes in mortality (or death), unlike cohort life expectancy. The period life expectancy measure assumes that the number of people in any age group who die in one year will be the same the following year and so on. For example, many people died from COVID-19 in 2020, but with vaccines and other improved methods of prevention and treatment, the number of deaths may be less in 2021. If this is true, the period life expectancy would likely increase again. On February 25, 2020, the U.S. CDC reported that the period life expectancy in the United States fell by a full year in the first six months of 2020 -- from 78.8 years in 2019 to 77.8 years. This period life expectancy reflects the average life expectancy for an infant born in 2020. The value does not mean that everyone who is alive now will die one year earlier. Changes in period life expectancy were reported between males and females. In 2019, female period life expectancy was 5.1 years higher than for males (76.3). In 2020, female period life expectancy was 5.4 years higher than for males (75.1 years for males and 80.5 years for females). Differences in life expectancy were also reported based on  race and ethnicity. Life expectancy decreased most for Black individuals, then Latino individuals, then white individuals. As a result of these differences in decreases, the Latino population had a lower period life expectancy advantage compared to the white population by about a year as of the first half of 2020. The white period life expectancy advantage compared to the black population increased by nearly two years to a 6 year difference overall. This is the widest period life expectancy has been between Black individuals and white individuals in the population since 1998. The CDC life expectancy estimates were specifically based on information for the first half of 2020. When remeasured in 2021, life expectancy as well as cohort life expectancy are likely to decrease alongside decreases in COVID-19 deaths and increases in COVID-19 vaccinations. 

Can the COVID-19 vaccine lead to lethal thrombocytopenia?

As of the end of January 2021, 36 cases of the blood disorder Immune thrombocytopenic purpura (ITP) have been reported to the U.S. government’s Vaccine Adverse Event Reporting System (VAERS). The cases have involved both the Pfizer-BioNTech and the Moderna vaccine, which are the two vaccines currently approved for emergency use in the U.S.  It is too soon to know whether or not the timing of ITP and COVID-19 vaccination were coincidental in these cases. It's also not clear if vaccination led to an exacerbation of pre-existing unrecognized ITP, or if the vaccination caused ITP. Some hematologist experts in ITP have noted that they suspect the vaccine played a role in the onset of ITP, particularly given that viral infections can cause ITP, and given that similar reactions have occurred after pneumococcal, MMR, and other vaccinations. However, if there is an association, these cases are likely to be extremely rare. They may also be the result of a predisposition to ITP that is unknown before the onset of the condition, especially as it’s possible to have low platelet count without symptoms.  Given the low number of cases, it is likely more cases would be needed to better understand any association between the vaccines and ITP and to establish a causal link, if there is one. Pfizer and Moderna have both put out statements that they are continuing to collect and monitor safety data from the public, and Pfizer has specifically stated “we have not been able to establish a causal association with our vaccine. Immune thrombocytopenic purpura (ITP), is a disorder of the blood that is characterized by a decrease in platelets (cells that help to stop bleeding) within the blood. A decrease in platelet count can result in easy or excessive bruising, bleeding from the gums or nose, and internal bleeding. A rare complication of ITP is bleeding into the brain, which can be deadly. ITP typically affects approximately 0.01% of the adult population. The condition, which is generally treatable, emerges when one’s immune system attacks platelets or the cells that create platelets. The reasons for why the immune system begins attacking platelets or the cells that create them is not well known; sometimes it follows a viral illness, for instance, and can last for months or become chronic and persist for years. 

What do we know so far about the variant of COVID-19 first identified in South Africa?

There are many thousands of COVID-19 virus variants that exist, most of which are not concerning. However, experts are concerned about a variant that is dominant in South Africa, also known as 501.V2 or B.1.351.  This variant was first identified in Nelson Mandela Bay, South Africa, in samples that date back to the start of October 2020. It has since become the dominant virus variant in the Eastern and Western Cape provinces of South Africa and spread outside of South Africa to at least 20 countries, including the U.S., Norway, Japan, the U.K., and Austria. Most variants are not significant and in some cases can even weaken the virus. The South African variant is one that appears to be more contagious and more evasive of current vaccines. Its contagiousness is due to a mutation in the virus's spike protein that makes it easier to spread. The UK variant also has this protein, making the variants similar. There is no evidence so far to suggest that the South African variant causes more severe or more deadly cases of COVID-19. In a pre-print study of the Pfizer vaccine using blood samples from vaccinated individuals studying protection against two of the South Africa variant mutations, efficacy was just slightly less than the original 95%. Early results from a Moderna study of the vaccine’s efficacy against the variant suggest around the same efficacy (94.1%), although the immune response may not be as strong or prolonged.  Early results for Novavax and Johnson & Johnson suggest some protection but reduced. Testing for the Novavax vaccine suggests a reduction from 89.3% efficacy against the virus to 60.1% efficacy against the variant, and early results from the Johnson & Johnson testing suggest a reduction from 72% efficacy to 52%. And finally, preliminary data on protection from Oxford’s AstraZeneca's vaccine suggests that it offers limited protection against the South Africa variant when mild disease is triggered, but experts state that it should still protect against severe disease.

What do we know about controlling the spread of COVID-19 through hyper-local measures?

Imposing restrictions at a hyper-local level, such as by postal code or zip code, can work to contain COVID-19, but is not without challenges and comes with a set of both pros and cons. The pros come into effect if individuals who are residents of that zip code or neighborhood a) follow the restrictions imposed and do not travel outside their neighborhood, especially at a mass level. The cons come into effect if individuals who are residents of that zip code or neighborhood either do not follow restrictions imposed, or travel outside their neighborhood, especially at a mass level. As a result, it’s crucial to communicate with residents so that they understand the expectations and what is at risk if local measures aren’t followed. To help ensure that they are followed, local public health officials and leaders must share information with residents on how to access the resources that they need hyper-locally, both for healthcare and otherwise, so that individuals are not pushed to seek resources outside of their affected area, and in turn potentially increasing positive rates in other neighborhoods, worsening the problem overall.  Of note is that hyperlocal surveillance of COVID-19 is also useful for tracking and ultimately controlling the spread of the virus, as the more local the data is, the more granular it is likely to be and the less gaps it is likely to have.

Does COVID-19 impact young people?

The virus that causes COVID-19 can infect people of all ages. Although older people are known to be more likely to have severe side effects of the virus, that does not mean young people are not at risk of getting sick, or even dying, from COVID-19. In addition, young people, including children, may spread COVID-19 to relatives and contacts who may be older or have other risk factors. Young people with underlying health conditions are at higher risk of severe COVID-19, but young people with no prior health issues have also been impacted by the disease. Less severe COVID-19 can lead to lingering health impacts that have prevented some young people from going to school, working and resuming other normal activities for months. As of December 3, 2020, over 1.4 million US children have tested positive for COVID-19. In total, children have accounted for 12% of US COVID-19 cases though there was a 23% increase in child COVID-19 cases recorded between November 19 and December 3, 2020. In spite of the recent increase, the incidence of severe illness in children remains uncommon, though it is possible. In a study of 85,000 COVID-19 cases in India, almost 600,000 of their contacts showed that children of all ages can become infected with COVID-19 and spread it to others. More than 5,300 school-aged children in the study had infected 2,508 contacts. More evidence is emerging on how some young people develop severe symptoms and complications related to COVID-19, and are contributing to the widespread transmission of the virus. Young people should take preventive measures, including wearing face masks (recent guidance from the U.S. Centers for Disease Control and Prevention suggests wearing a cloth mask over a surgical mask or a high quality respirators), practicing social distancing (6 feet/2 meters), avoidance of crowds, and frequent hand-washing, to prevent the spread of COVID-19. These measures are suggested for their own protection as well as for preventing the spread of COVID-19 to others.

What do we know so far about airborne transmission and how does it differ from respiratory droplet transmission?

There is increasing evidence that COVID-19 can spread through airborne transmission, which is when a person infected with COVID-19 releases tiny droplets of fluid into the air called 'droplet nuclei' by coughing, sneezing, talking, or during some medical appointments and procedures. Droplet nuclei are very light, relatively dry, and microscopic in size so they can remain suspended in the air like a mist, which is why airborne transmission is also called 'aerosol transmission.' This is different from the main theory that the virus spreads through bigger respiratory droplets that are heavier, fall to the ground relatively quickly, and do not remain suspended in the air or spread through the air.  While researchers are continuing to study aerosol transmission of COVID-19, the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) acknowledged evidence of airborne transmission in poorly ventilated spaces. Enclosed spaces have been found—through scientific studies as well as case studies—to contain enough virus to cause infections in people more than six feet apart, or who passed through a space soon after an infectious person left the room.  One study conducted at the University of Nebraska Medical Center collected air and surface samples from the rooms of isolated individuals to examine viral shedding, and found evidence of the novel coronavirus in the air from isolated individuals who had COVID-19 (including at a distance from the infected individual and outside of their room in the hallway). As a second piece of evidence, a study from Singapore found that COVID-19 virus aerosol particles were found in two "airborne infection isolation rooms" in hospital wards, despite these rooms being intentionally well ventilated to prevent transmission. In a study that modeled the transmission of COVID-19 during the outbreak on the Diamond Princess cruise ship in early 2020, researchers found that aerosol inhalation of the virus was likely the dominant contributor to COVID-19 transmission among passengers.  Another study outlined the case of the Skagit Valley Chorale rehearsal in Mount Vernon, Washington, which took place in early March 2020 and resulted in 45 out of 60 members of the chorus testing positive for or showing COVID-19 symptoms after a 2 ½ hour indoor practice session. No attendees reported physical contact between members, as person-to-person contact and touching of surfaces was intentionally limited. No one was located within 3 meters in front of the index COVID-19 case, where larger respiratory droplets from that individual would have likely landed. The authors concluded that inhalation of infectious respiratory aerosol from shared air was the leading mode of transmission and that dense occupancy, long duration, loud vocalization, and poor ventilation increased risk.  Another case study was reported in China in early February when a who passed by the door of a symptomatic patient several times person contracted COVID-19. Finally, one China-based study compared risks of COVID-19 outbreak among 126 passengers taking two buses on a 100-minute round trip. Compared to individuals in the non-exposed bus (Bus #1), those in the exposed bus (Bus #2) were 41.5 times more likely to be infected, suggesting airborne transmission of the virus, particularly given the closed environment with air recirculation and lack of contact between passengers.  These studies, and others like them, highlight the importance of combining proper ventilation with cloth masks and social distancing to prevent transmission of the virus. The U.S. CDC's most recent guidelines suggest wearing a cloth mask over a surgical mask or an individual KN95/N95 mask as these methods can offer the most protection from the virus, but any mask offers substantially more protection than not wearing one. Studies such as these are particularly important as it would not be ethical to run a randomized control trial (RCT) to test different transmission modes in infecting individuals, and given that it’s difficult to specifically pinpoint in a study how someone was infected without a highly controlled environment, such as that of an RCT. Public health experts have repeatedly warned that airborne transmission is most likely contributing to transmission, especially in indoor spaces, and recommendations should incorporate the need for sufficient ventilation, high-efficiency filtration, and limiting crowded spaces, in addition to universal adoption of masks, social distancing, and frequent handwashing with soap and water.

Is it safe to wear a mask?

Wearing a face mask is both safe and recommended to slow the spread of COVID-19. The United States Centers for Disease Control recommends widespread use of cloth face coverings over surgical masks to prevent spread from people who might have the virus that causes COVID-19 without realizing it. While N95 masks are in short supply and should be reserved for healthcare workers, cloth face coverings should always be worn when interacting with other people in close proximity (including but not limited to grocery shopping, ordering food at a restaurant, interacting with people within 6 feet in outdoor spaces). You should clean your hands before touching the mask, make sure the mask covers your nose and mouth, and ensure the mask fits tightly on your face without leaving exposed spaces. Additionally, you should avoid touching the front of the mask, avoid taking the mask off when talking to other people; only remove the mask by touching the straps; wash your hands after removing the mask; wash the mask in soap and detergent with hot water at least once a day; and avoid sharing masks with others or leaving used masks around other people. While mask wearing is recognized as safe and is advised by the World Health Organization and other leading health advisory groups, there are cases where masks should not be used. For instance, masks are not safe for children under 2 years of age, people who have trouble breathing in general, or individuals who are unconscious or who would be unable to remove the mask without help.  Several cities and states, such as New Orleans and Washington, have mandated the use of face masks to slow the spread of the virus. However, masks alone are not enough. In addition to wearing a mask to help stop the spread of the virus, public health experts encourage social distancing (staying at least 6 feet (2 meters) away from others) as well as frequent and thorough hand washing.

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