Sara Grossman, PharmD

Vaccines are a critical means of preventing disease-related morbidity and mortality,

 providing individual and herd immunity, and decreasing the burden of certain diseases.

 While vaccination is important at every age, it is especially important for older adults: As people age, their immune system weakens, making them more vulnerable to infections. Likewise, age-related comorbidities may increase the risk of complications from illnesses.


Preventive medicine is the most effective strategy to protect the health of older adults, and vaccination is one of the most feasible approaches.

 Read on for an overview of current vaccination recommendations for adults 65 years and older and strategies to ensure the effective vaccination of this population.

The CDC provides recommendations for immunization practices, which are available on the CDC website.

 Specific recommendations are made based on age group as well as on medical condition and other indications. A summary of the CDC recommendations for those 65 years and older is presented in the 

Table. Routine Vaccinations for Individuals 65 Years and Older

The COVID-19 vaccine reduces the risk of contracting and spreading SARS-CoV-2 and decreases the risk of serious illness. The dosing regimen differs based on the specific product that is used. The CDC updated its recommendations in late December 2021 to include a clinical preference for the Pfizer-BioNTech or Moderna mRNA vaccines over the Johnson & Johnson vaccine.

 The CDC also recommends a single booster dose of the COVID-19 vaccine.

At press time, individuals who received the Pfizer-BioNTech vaccine are eligible to receive a booster dose 5 months after their completed series,9 and those who received the Moderna vaccine, after 6 months. Individuals who received the Johnson & Johnson vaccine are eligible to receive a booster dose beginning 2 months after their initial vaccination.

Because of the uncertainty about the duration of protection and the emergence of new variants of the virus, recommendations for booster doses of the COVID-19 vaccine may change.


All individuals 65 years and older should receive an annual influenza vaccine, ideally by the end of October but no earlier than September because of concerns of waning immunity.

 During the 2017-2018 flu season, nearly 80% of influenza-related deaths were in individuals 65 years or older.12 The CDC recommends the influenza inactivated vaccine (IIV) or the influenza recombinant vaccine (RIV4) in adults over 50 years; the influenza live attenuated vaccine (LAIV4) is not recommended in this population.

A tetanus and diphtheria (Td) booster, with or without pertussis, is recommended every 10 years. Individuals who have not been previously vaccinated with tetanus, diphtheria, and pertussis (Tdap) at or after the age of 11 should receive 1 dose of Tdap followed by Td or Tdap boosters every 10 years.

The risk for developing herpes zoster increases with age.13 As such, it is recommended that adults 50 years and older receive a 2-dose series of the recombinant zoster vaccine (Shingrix) spaced 2 to 6 months apart, regardless of previous herpes zoster infection or previous administration of a live zoster vaccine (Zostavax, ZVL).

The overall case-fatality rate for pneumococcal bacteremia is about 20% among adults; this rate may be as high as 60% among older patients.14 The CDC currently recommends 1 dose of the pneumococcal polysaccharide vaccine (PPSV23) for all adults 65 and older. If PPSV23 was administered prior to age 65, the dose of PPSV23 should be administered at least 5 years after the previous dose. A dose of PCV13 may also be considered in addition to PPSV23 in those who did not receive PCV13 previously; a determination concerning its administration should be based on shared clinical decision-making. In patients requiring both vaccines, PCV13 should be administered first, at least 1 year before the PPSV23 vaccine.

In addition to the aforementioned vaccines recommended for most adults 65 years and older, the CDC recommends other vaccines—including varicella, hepatitis A, hepatitis B, MenACWY (meningococcal A, C, W, Y), MenB (meningococcal B), and 

 type b5—for those with certain risk factors or other indications.


There are several reasons elderly adults may not be vaccinated according to CDC recommendations. Patient-related factors include lack of awareness of declining immunity or the importance of vaccines in this age group, lack of familiarity with vaccine recommendations, the belief that a healthy lifestyle can take the place of vaccines, worries about vaccine safety, underestimation of the impact of vaccine-preventable diseases on health, concerns about cost, and mobility issues preventing the individual from getting to a vaccination site.

Provider-related issues and other systematic issues include lack of familiarity with vaccine recommendations, lack of promotion of vaccination to patients, limited access to immunization records, and availability of a vaccine at the provider’s practice site.

Overcoming barriers to vaccination among older individuals means addressing patient-level, provider-level, and systematic issues. Key to the success of vaccination efforts is buy-in from the patient; effective patient education and encouragement can help facilitate this. Health care professionals should identify knowledge gaps and patient concerns, achieved via motivational interviewing that alleviates concerns. Inform patients that Medicare Part B covers influenza and pneumococcal vaccines, as well as other vaccines for those who are at increased risk. Vaccines may also be covered by Medicare Part D, Medicaid, or private insurers.

At the provider level, attaining the proper education and training necessary to effectively address vaccination needs in the community can help. Keeping current with the CDC’s recommendations is essential. Providers must maintain complete and up-to-date patient records, ensure sufficient supply of properly stored vaccines. Providers must also be proactive in examining patient history and screening for immunization needs. Although this should be an ongoing process, it may be instrumental to designate a particular visit to ensure that an overall assessment of patient immunization status is performed.

armacists are uniquely positioned to play a significant role in vaccination efforts. Community pharmacies are convenient vaccination sites, staffed with trusted professionals who are knowledgeable and trained.

On a systemic level, government and social agencies and the health care community should work to facilitate successful vaccination programs. Those who live in community-based group homes or who receive home health care should be included in vaccination outreach programs. Involving caregivers is also important. Vaccines should be offered at convenient locations: senior centers, community centers, or independent living facilities for older adults. Pay special attention to those who are homebound, and to people living in rural or remote areas. Lastly, create effective communication material specifically geared for this population; this is likely to be instrumental in maximizing the impact of these efforts.

Older adults are among the most vulnerable populations. By leveraging expertise to advocate for and facilitate vaccine administration, pharmacists are poised to ensure widespread vaccination in this cohort.


View the rest of our February 2022 issue here

Weinberger B. Vaccines for the elderly: current use and future challenges. 

. 2018;15:3. doi:10.1186/s12979-017-0107-2

Why vaccinate? The history of vaccines. The College of Physicians of Philadelphia. Updated January 25, 2018. Accessed January 3, 2022. 

https://www.historyofvaccines.org/content/articles/why-vaccinate

Adults age 65 and older. US Department of Health & Human Services. Updated April 29, 2021. Accessed January 3, 2022. 

https://www.hhs.gov/immunization/who-and-when/adults/seniors/index.html

Ciabattini A, Nardini C, Santoro F, Garagnani P, Franceschi C, Medaglini D. Vaccination in the elderly: the challenge of immune changes with aging. 

. 2018;40:83-94. doi:10.1016/j.smim.2018.10.010

Adult immunization schedule. CDC. Updated February 12, 2021. January 3, 2022. 

https://www.cdc.gov/vaccines/schedules/hcp/imz/adult.html

Types of vaccines available. CDC. Updated December 29, 2021. Accessed January 3, 2022. 

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines.html

CDC endorses ACIP’s updated COVID-19 vaccine recommendations. News release. CDC. December 16, 2021. Accessed January 3, 2022. https://www.cdc.gov/media/releases/2021/s1216-covid-19-vaccines.html

CDC expands eligibility for COVID-19 booster shots. News release. CDC. October 21, 2021. Accessed January 3, 2022. 

https://www.cdc.gov/media/releases/2021/p1021-covid-booster.html

CDC recommends Pfizer booster at 5 months, additional primary dose for certain immunocompromised children. CDC. News release. January 4, 2022. Accessed January 4, 2022. https://www.cdc.gov/media/releases/2022/s0104-Pfizer-Booster.html

COVID-19 vaccine booster shots. CDC. Updated December 28, 2021. Accessed January 3, 2022. 

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/booster-shot.html

Key facts about flu vaccines. CDC. Updated November 18, 2021. Accessed January 3, 2022. 

https://www.cdc.gov/flu/prevent/keyfacts.htm

Frank T. Flu deaths rising for Americans over 65. AARP. October 2, 2018. Accessed January 3, 2022. 

https://www.aarp.org/health/conditions-treatments/info-2018/older-flu-deaths-rising.html

Shingles. Mayo Clinic. September 17, 2021. Accessed January 3, 2022. 

https://www.mayoclinic.org/diseases-conditions/shingles/symptoms-causes/syc-20353054

Pneumococcal vaccines (PCV13 and PPSV23). Immunization Action Coalition. Updated October 22, 2020. Accessed January 3, 2022. 

https://www.immunize.org/askexperts/experts_pneumococcal_vaccines.asp

Aging and immunity: the important role of vaccines. American College of Physicians. Accessed January 3, 2022. 

https://www.acponline.org/system/files/documents/clinical_information/resources/adult_immunization/aging_and_immunity_guide.pdf

Ventola CL. Immunization in the United States: recommendations, barriers, and measures to improve compliance: part 2: adult vaccinations. 

Tak CR, Marciniak MW, Savage A, Ozawa S. The essential role of pharmacists facilitating vaccination in older adults: the case of herpes zoster. 

. 2020;16(1):70-75. doi:10.1080/21645515.2019.1637218

Jurisdictions: Vaccinating older adults and people with disabilities. CDC. Reviewed August 26, 2021. Accessed January 3, 2022. 

https://www.cdc.gov/vaccines/covid-19/clinical-considerations/older-adults-and-disability/access.html

Articles

Vaccines are important for everyone, but they’re critical for adults older than 65 years. 

Review: Vaccine Guidelines for Older Adults

Since the onset of the COVID-19 pandemic, emphasis has been placed on monitoring health status, screening for disease states, and ensuring that the general public is not exposed to the virus and/or exhibiting signs and symptoms of COVID-19. One of the methods used to detect illness and prevent the spread of the disease is monitoring for fever with the use of thermometers. According to IRI, a Chicago-based market research firm, the sale of personal thermometers increased by 297% during the 4-week period ending March 22, 2020, compared to the same time period 1 year earlier.

 Since COVID-19 remains a public concern, it is important for pharmacists to be familiar with the various types of thermometers available on the market and to provide proper guidance on their use.

The body maintains a state of homeostasis regulated by the hypothalamic thermoregulatory center. The center balances excess heat production from metabolic activity in the muscle and liver by allowing heat to be released from the skin and lungs to maintain a mean oral temperature of 36.8

 0.7o F). Fluctuations in body temperature occur throughout the day, with temperature being lower in the morning and higher in the evening.

 Furthermore, the temperature considered to be fever differs based on the measurement site (

Body Temperature per Site of Measurement

Considerations When Selecting a Thermometer

Various thermometers are available on the US market. When selecting a thermometer, identifying one that will provide an accurate reading is most important. Since the FDA regulates thermometers as medical devices, all approved thermometers are considered accurate and reliable, when used appropriately.

 To do so, considerations must be given to the ease of use, which may be a function of the site of temperature measurement. Thus, consideration should be given to the versatility afforded by certain thermometers, allowing for measurements to be obtained in more than one body site. The following is a discussion of various types of thermometers. 

Rectal thermometers have been generally accepted as the “gold standard” for measuring temperature in very young children; however, some caregivers refrain from using them due to their intrusive nature and associated risks. These risks may include the development of peritonitis, rectal or intestinal perforation, and retaining of the thermometer inside the rectum.

 Rectal temperature measurements should not be taken in patients with obstructive hemorrhoids or diarrhea, as well as in patients with neutropenia due to their increased susceptibility to infection. Other considerations when measuring rectal temperature are that it is cumbersome and time consuming and that rapid changes in body temperature may not be detected due to the large muscle mass and poor blood flow to the rectal area.

 Notably, rectal temperatures tend to run higher than oral temperatures.

Oral thermometers are commonly used in medical offices and within households. However, to obtain accurate readings, certain factors must be kept in mind. For instance, oral temperature readings should be obtained at least 20 to 30 minutes after drinking and/or eating and should not be taken in patients who have a difficult time keeping the thermometer under their tongue and/or difficulty creating a tight seal around the thermometer.

 For younger patients who may struggle with these issues, pacifier thermometers are an alternative option to measure temperature. To obtain a proper reading with a pacifier thermometer, patients should wait 30 minutes after eating or drinking and should hold the pacifier in their mouth without moving it for 2 to 6 minutes.

 Lastly, oral temperatures should not be obtained in patients who are hyperventilating, uncooperative, lethargic, confused, and/or those who have had recent oral surgery.

Tympanic thermometers are usually used in pediatric offices to take the temperature via the ear. These provide a relatively quick and accurate measurement because the ear is close to the hypothalamus which allows for an accurate reading of core body temperature.

 However, proper positioning of the thermometer is extremely important to ensure an accurate reading. Other factors such as inflammation of the ear canal, age (children younger than 6 months do not have fully developed ear canals), and earwax buildup may also affect temperature readings.

 Additionally, cold or hot weather can affect temperature readings so it is recommended to wait at least 15 minutes after being exposed to extreme temperatures before using the thermometer.

Proper technique requires the user to pull the ear backward to help straighten the ear canal and to aim the tip of the probe towards the patient's eye on the opposite side of his or her head.

Temporal touch thermometers use an infrared scanner to scan the temporal artery in the forehead. This task is completed by placing the thermometer on 1 side of the forehead and then moving it across the forehead; the process usually takes a few seconds. This method of measuring temperature can be very sensitive in detecting fever but the scanner needs to be in contact with the skin at all times. Overall, this method provides an easy and accurate temperature reading in most patients.

 Yet, one must keep in mind that direct sunlight, cold temperature, sweaty forehead, and poor technique can impact the accuracy of the reading.

Noncontact temporal thermometers also use infrared technology but these do not require direct contact with the skin. Thermometers are generally held between 1.2 and 6 inches from the skin.

 Using a forehead noncontact infrared thermometer is quick, convenient, noninvasive, and carries a low risk of disease transmission. Studies suggest that taking temperature immediately after coming in from the cold underestimates body temperatures and as such, infrared temporal thermometers are not ideal for screening for diseases during cold weather.

 To ensure accuracy, measurements should be taken at least 10 minutes after coming in from the cold.

 These thermometers should also be used in environments free from secondary infrared sources, such as direct sunlight and incandescent lamps.

Axillary temperatures usually run lower than oral temperatures. Compared with the rectal and oral methods of measuring temperature, axillary thermometers are less reliable at detecting fevers.

 Although they may be favored because of their ease of use and noninvasive nature, their use should be discouraged because of concerns with accuracy.

 When used, temperatures should not be taken directly after vigorous activity or bathing since these can alter body temperature.

Basal thermometers are used to monitor basal body temperature for the purpose of tracking ovulation in women who are trying to conceive or prevent pregnancy.

 The digital basal thermometers have smaller gradations than regular thermometers (0.1 degree vs 0.2 degree), enabling them to detect small changes in body temperatures. This is important since the temperature increase that follows ovulation is small (approximately 0.4 to 1.0

Temperature can be taken orally, rectally, or vaginally; however, the same site must be used each day. Temperature must also be taken at approximately the same time each morning before rising, after at least 3 hours of sleep.

Color change thermometers usually involve placing a strip on the forehead, which changes color according to the heat radiating from the body. These thermometers are easy to use, provide a quick reading, and are sometimes reusable. However, they can be inaccurate as they do not reliably detect changes in the core temperature but only changes in skin temperature.

Glass Thermometers vs Digital Thermometers

Two types of glass thermometers are available, one with mercury and the other without it. Mercury-containing thermometers are no longer recommended due to toxic effects and may be banned in some states.

 Notably, though, individuals may still have access to these thermometers at home. Before taking measurements, it is important to ensure that the thermometer’s mercury is at the bottom of the measurement column. If this is not the case, the thermometer should be flicked to bring down the mercury in the column. Mercury-free glass thermometers use a gallium-indium-tin alloy, as a substitute for mercury.

 Glass thermometers differ in their tips. Those that utilize a long, thin tip are indicated for oral and axillary use whereas those with a short, round tip are for rectal use.

Digital thermometers are commonly used as an alternative to glass thermometers since they are faster, easier to read, and remove the environmental concern of mercury.

 Furthermore, there are no clinically significant differences between the accuracy of glass thermometers and digital thermometers.

 Digital thermometers are portable and can be used to measure oral, axillary, and rectal temperatures.

Several factors should be considered when selecting a thermometer. Thermometers vary in their mechanisms of measuring temperatures and in their intended uses. Pharmacists must be familiar with the different thermometers so they can ensure proper use by the consumer.

1. COVID-19 and the Economy: Tacking the Dramatic Pivot of U.S. Consumer and Shopper Behavior. IRI Worldwide. Published April 3, 2020. Accessed May 12, 2021. https://www.iriworldwide.com/iri/media/library/covid-19-thought-leadership-4-3-2020.pdf

2. Dinarello CA, Porat R. Fever. In: Jameson JL, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J, eds. 

Harrison’s Principles of Internal Medicine

, 20th ed. McGraw Hill: 2020. Accessed March 16, 2021.

3. Lemay V, Feret BM. Fever. In: Krinsky DL, ed. 

Handbook of Nonprescription Drugs: An Interactive Approach to Self-Care.

 19th ed. APhA Publications; 2018:97-110. 

4. Temperature: Digital and Glass Thermometers. Nationwide Children’s. Updated February 2017. Accessed March 24, 2021. https://www.nationwidechildrens.org/family-resources-education/health-wellness-and-safety-resources/helping-hands/temperature-digital-and-glass-thermometers

5. Thermometers: Understanding the Options. Mayo Clinic. Updated November 17, 2020. Accessed March 25, 2021. https://www.mayoclinic.org/diseases-conditions/fever/in-depth/thermometers/art-20046737

6. Non-Contact Temperature Measurement Devices: Considerations for use in Port of Entry Screening Activities. Centers for Disease Control and Prevention. Published August 22, 2014. Accessed March 19, 2021. https://stacks.cdc.gov/view/cdc/24857/cdc_24857_DS1.pdf

7. Dzien C, Halder W, Winner H, Lechleitner M. COVID-19 screening: are forehead temperature measurements during cold outdoor temperatures really helpful? 

. 2021;133(7-8):331-335. doi: 10.1007/s00508-020-01754-2.

8. Erenberk U, Torun E, Ozkaya E, Uzuner S, Demir AD, Dundaroz R. Skin temperature measurement using an infrared thermometer on patients who have been exposed to cold. 

 2013;55(6):767-770. doi: 10.1111/ped.12188

9. Briggs GC. Home Testing and Monitoring Devices. In: Krinsky DL, ed. 

 19th ed. APhA Publications; 2018:899-922. 

10. Basal Body Temperature for Natural Family Planning. Mayo Clinic. Updated March 3, 2021 Accessed May 26, 2021. https://www.mayoclinic.org/tests-procedures/basal-body-temperature/about/pac-20393026

11. Mercury Thermometers. US Environmental Protection Agency. Updated March 30, 2021. Accessed June 9, 2021. 

https://www.epa.gov/mercury/mercury-thermometers

12. Baura G. Thermometers. In: Baura G, ed. 

Medical Device Technologies: A System Based Overview Using Engineering Standards.

 2nd ed. Academic Press; 2020; doi: 10.1016/B978-0-12-811984-6.00012-X

13. Hardu G, Murugan R. Is there a significant difference between digital and glass mercury thermometers? 

Pharmacists must be familiar with the different thermometers so they can ensure proper use by the consumer. 

Thermometers: A Review

Back in December 2020, the FDA issued an emergency use authorization for Pfizer-BioNTech’s COVID-19 vaccine, followed by authorization for the Moderna and Janssen (Johnson & Johnson) vaccines. Many Americans have yet to be vac- cinated, with the most common reasons for refusing being fear of potential adverse effects (AEs) and concerns about the rapid vaccine development process.

Pharmacists must be familiar with the safety profiles of the vaccines to assure the public of their safety.

COVID-19 Vaccines Available in the United States

Three vaccines are currently available on the US market. The Pfizer and Moderna vaccines are both messenger RNA (mRNA) vaccines, whereas the Janssen is a viral-vector vaccine.

 All 3 result in the production of SARS-CoV-2 spike proteins, which trigger the development of antibodies. The development of immunity and memory cells typically takes a few weeks and, when complete, these protect the body against COVID-19 infections.

 Although the vaccines stimulate an immune response, they do not cause a full COVID-19 infection.

Before a vaccine receives FDA approval, it undergoes a series of trials during which its efficacy and safety profiles are established. Trials begin in animal models and continue with 3 phases of clinical trials. A vaccine gains FDA approval only if the efficacy and safety data prove that its benefits outweigh the risks. Once a vaccine has been approved and launched, postmarketing surveillance begins. Such surveillance allows for the collection of safety data in a larger and more diverse population.

Postmarketing safety information for COVID-19 vaccines has been gathered in several ways. For all vaccines, the FDA’s Center for Biologics Evaluation and Research monitors vaccine safety through passive and active surveillance.

 Passive surveillance consists of adverse event reports received from the public and health care professionals, which are entered into the Vaccine Adverse Event Reporting System. Active surveillance involves proactively obtaining and analyzing information from large health care data systems to verify safety signals identified through passive surveillance or to detect additional safety signals. If a possible link between a vaccine and an AE is identified, public health officials assess the benefits and risks and determine whether the vaccine can continue to be administered and whether administration guidelines require adjustment.

Reported Adverse Effects Associated With COVID-19 Vaccines

The AEs reported with the COVID-19 vaccines are generally mild and resolve within a few days.

 These effects tend to be more intense after the second dose of the mRNA vaccines and are more likely to occur in younger individuals. Ongoing surveillance has identified additional AEs, but it is not always possible to reliably estimate their frequency or establish a causal relationship to vaccine exposure (see 

 This point can be illustrated by the reporting in mid-April 2021 of a few cases of thrombocytopenia with cerebral venous sinus thrombosis in individuals who had received the Janssen COVID-19 vaccine. Although these cases appear to be very rare, as of the time of this writing, the FDA and CDC have recommended a pause in the use of this vaccine until this matter is thoroughly investigated.

The more commonly reported AEs associated with the use of COVID-19 vaccines are usually related to the vaccine’s pharmacology and not considered immune-mediated or allergic reactions.

 Despite that, news reports concerning severe postmarketing reactions including anaphylaxis instilled fear among the public.

Anaphylaxis is a severe acute-onset immunologic reaction, generally immunoglobulin E (IgE) mediated, which typically occurs in response to preformed IgE antibodies.

 Acute-onset immunologically mediated reactions commonly manifest as urticaria, swelling, gastrointestinal upset, respiratory distress, or cardiovascular collapse associated with severe cases of anaphylaxis. The onset of acute allergic reactions generally occurs within 30 minutes of exposure, although a reaction may also develop hours to days later, in which case it usually presents as a cutaneous reaction. Generally, the mRNA, DNA, or other antigen components in vaccines are not the culprits for allergic reactions. Allergic reactions are usually attributed to other product components such as stabilizing agents and adjuvants, and, rarely, to latex in the vial’s rubber stopper. The Pfizer and Moderna COVID-19 vaccines contain mRNA, lipids, polyethylene glycol (PEG) 2000, electrolytes, sucrose, and a saline diluent. Although the etiology of anaphylaxis to the COVID-19 vaccines is not known, PEG and related polysorbates have been associated with cases of anaphylaxis to other agents. Individuals who exhibit signs of allergic reaction after COVID-19 vaccination are advised to avoid new PEG exposure and to undergo further evaluation with a board-certified allergist or immunologist.

Although cases of anaphylaxis were not reported in clinical trials with the mRNA vaccines, 21 incidents of possible anaphylaxis were subsequently reported with the Pfizer vaccine (11.1 cases per million doses), with 70% occurring within 15 minutes of administration.

 Ten cases of possible anaphylaxis were reported after vaccination with the Moderna vaccine (2.5 cases per million doses) and 1 case of anaphylaxis was reported with the Janssen vaccine.

 The less extensive use of the Janssen vaccine to date prohibits a comparative assessment of the overall safety of this vaccine relative to the mRNA vaccines.

The CDC recommends that the COVID-19 vaccines not be administered to individuals who have a history of severe or immediate allergic reaction to any vaccine component (eg, PEG in the case of the mRNA vaccines, polysorbate in the case of the Janssen vaccine).

 Patients who experienced a severe or immediate allergic reaction to a COVID-19 vaccine should not receive subsequent doses.

The CDC recommends a postvaccination observation period of 30 minutes for those at high risk for anaphylactic reactions and 15 minutes for all other individuals.

When providing counseling, it is important to emphasize the vaccine’s efficacy. Individuals receiving the mRNA vaccines also should be counseled on the importance of completing the vaccination series with the same product. They should be counseled on the expected postvaccination symptoms: Of those receiving the mRNA vaccines, local symptoms are experienced by 80% to 89%, and systemic symptoms by 55% to 83%; of those receiving the viral-vector vaccine, local symptoms are experienced by 50%, and systemic symptoms by 55%. Reassure recipients that systemic postvaccination symptoms are generally mild to moderate in severity, occur within the first 3 days of vaccination, and resolve within 3 days of onset. Advise recipients that antipyretic or analgesic medications can be taken for postvaccination local or systemic symptoms.

The available COVID-19 vaccines are effective in reducing the spread of the disease. Serious reactions are rare, and the public should be educated on the overall safety of these vaccines.

1. WHO coronavirus (COVID-19) dashboard. World Health Organization. Updated April 6, 2021. Accessed April 6, 2021. 

2. Nguyen KH, Srivastav A, Razzaghi H. COVID-19 vaccination intent, perceptions, and reasons for not vaccinating among groups prioritized for early vaccination–United States, September and December 2020. 

. 2021;70(6):217-222. doi:10.15585/mmwr.mm7006e3

3. Understanding how COVID-19 vaccines work. CDC. Updated March 9, 2021. Accessed April 1, 2021. 

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/how-they-work.html

4. COVID-19 vaccine safety surveillance. Food & Drug Administration. Updated February 9, 2021. Accessed April 1, 2021. 

https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/covid-19-vaccine-safety-surveillance

5. Ensuring the safety of vaccines in the United States. CDC. Updated January 2018. Accessed April 1, 2021

https://www.cdc.gov/vaccines/hcp/conversations/downloads/vacsafe-ensuring-color-office.pdf

6. Possible side effects after getting a COVID-19 vaccine. CDC. Updated March 16, 2021. Accessed April 2, 2021. 

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/expect/after.html

7. Pfizer-BioNTech COVID-19 Vaccine- bnt162b2 injection, suspension. DailyMed. Updated February 26, 2021. Accessed April 1, 2021. 

https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=908ecbe7-2f1b-42dd-94bf-f917ec3c5af8

8. Moderna COVID-19 Vaccine- cx-024414 injection, suspension. DailyMed. Updated March 29, 2021. Accessed April 1, 2021. 

https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=e0651c7a-2fe2-459d-a766-0d59e919f058

9. Janssen COVID-19 Vaccine- ad26.cov2.s injection, suspension. DailyMed. Updated April 2, 2021. Accessed April 6, 2021. 

https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14a822ff-f353-49f9-a7f2-21424b201e3b

10. Recommendation to pause use of Johnson & Johnson’s Janssen COVID-19 vaccine. Centers for Disease Control and Prevention website. Accessed April 15, 2021. 

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/JJUpdate.html

11. Kuder MM, Lang DM, Patadia DD. Anaphylaxis to vaccinations: a review of the literature and evaluation of the COVID-19 mRNA vaccinations. 

. Published online March 1, 2021. doi:10.3949/ccjm.88a.ccc075

12. Rolla G, Brussino L, Badiu I. Maintaining safety with SARS-CoV-2 vaccines. 

. 2021;384(10):e37. doi:10.1056/NEJMc2100766

13. Information about COVID-19 vaccines for people with allergies. CDC. Updated March 25, 2021. Accessed April 5, 2021. 

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/specific-groups/allergies.html

14. Interim clinical considerations for use of COVID-19 vaccines currently authorized in the United States. CDC. Last reviewed March 5, 2021. Accessed April 5, 2021. 

https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html

Ease patients’ concerns by being well versed in the safety profiles of each vaccine.

COVID-19 Vaccines: A Focus on Safety

In March 2020, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus was declared a global pandemic. Since then, the scientific community has been searching for methods of prevention, diagnosis, and treatment of the newfound virus. In the absence of proven treatments for coronavirus disease 2019 (COVID-19), a variety of pharmaceutical agents have been explored for their potential benefit. Alongside these pharmaceutical agents, a number of dietary supplements, such as vitamin C, zinc, and magnesium have been used as well. One particular vitamin that has caught the attention of both health care professionals and consumers is vitamin D. In this article, we will review the evidence describing a possible link between vitamin D and COVID-19.

Vitamin D is a fat-soluble secosteroid hormone that is primarily responsible for the maintenance of calcium and phosphorus homeostasis, which is important for bone health.

 Vitamin D3, or cholecalciferol, is produced in the skin through exposure to sunlight. Cholecalciferol is then converted to calcidiol (25-hydroxyvitamin D3) in the liver and then further converted in the kidneys to calcitriol (1,25-dihydroxyvitamin D3), the physiologically active form of vitamin D. 

In addition to the natural production of vitamin D3 in the body, exogenous vitamin D3 can also be obtained from dietary sources, such as eggs and fish, or from OTC supplements. Vitamin D2 (ergocalciferol) is another form of vitamin D that is available as prescription-only supplements. The serum concentration of vitamin D generally considered adequate for bone and overall health in healthy individuals is > 50 nmol/L (>20 ng/mL).

 It is estimated that 24% of the US population has vitamin D levels that are lower than 50 nmol/mL.

Groups at risk for having low vitamin D levels include older adults, those with limited sun exposure, individuals with dark skin, individuals with conditions that limit fat absorption, and those who are obese or have undergone gastric bypass surgery.

The Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine established recommended dietary allowances (RDAs) that are necessary to maintain proper bone health and calcium metabolism in healthy individuals.

 The daily RDA for vitamin D for adults 18 through 70 years of age is 15 mcg (600 IU). The RDA for adults 71 years and older is 20 mcg (800 IU) per day.

In addition to its impact on bone health, vitamin D’s actions on genes expressed by immune cells, coupled with circumstantial but considerable evidence linking vitamin D deficiency with COVID-19 severity, have led to speculations that vitamin D status may play a role in the management of COVID-19.

 To identify literature that examined the relationship between vitamin D and COVID-19, we conducted a search of PubMed using combinations of the following search terms: 

COVID, COVID-19, coronavirus, vitamin D, deficiency, SARS-CoV-2, cholecalciferol,

 In order to obtain the highest level of evidence, we limited our search to meta-analyses.

In a systematic review and meta-analysis of 6 retrospective studies

 Munshi et al. examined the relationship between vitamin D serum levels and COVID-19 severity and prognosis.

 The investigators reported that based on data from 376 patients who were included in the studies, a low vitamin D level was significantly associated with poorer patient outcomes and prognosis. The investigators thus concluded that diagnosis of vitamin D deficiency could be a helpful adjunct in assessing patients' potential for developing severe COVID-19.

In a systematic review and meta-analysis by Pereira et al, the investigators explored the association between vitamin D deficiency and the prevalence of COVID-19 as well as its association with disease severity.

 A total of 25 observational studies involving 8176 patients with COVID-19 were included in the meta-analysis. The investigators reported that vitamin D deficiency was not associated with the development of COVID-19 infection. In contrast, the investigators did observe a positive association between vitamin D deficiency and disease severity. The investigators also noted that there was no support for vitamin D supplementation in individuals with normal blood vitamin D values with the aim of prevention, prophylaxis, or reducing the severity of the disease.

Liu et al. performed a systematic review and identified 10 case-controlled studies that were included in a meta-analysis aimed at examining the association between COVID-19 and vitamin D deficiency; a total of 376,596 subjects were included in this analysis.

In this article, we will review the evidence describing a possible link between vitamin D and COVID-19. 