VACCINES

The WHO notes that vaccines are a critical tool in the battle against viral diseases, including COVID-19 (WHO, 2021c). Thus, it is important for healthcare professionals to have a general understanding of vaccines, including their effectiveness against variants, types of vaccines, and common reasons individuals may hesitate to receive a vaccine.

Effectiveness Against Variants

Concerns about the effectiveness of COVID-19 vaccines against variants are widespread. When people hear the words mutation and variants, they may assume that something seriously different about the changed virus will render a vaccine ineffective.

In reality, although vaccines may be somewhat less effective against some COVID-19 variants, vaccines have clear public health and lifesaving benefits for the public. COVID-19 vaccines have been, or are being, tested against many different coronavirus mutations, and research indicates that vaccines already authorized or currently in development will be effective even with a fair amount of antigenic drift in the SARS-CoV-2 virus. Therefore, people should not avoid vaccination because of concerns about new variants (Elterman, 2021; WHO, 2021c; Nightengale, 2021).

Types of Vaccines

There are several basic strategies used to make vaccines. One type of vaccine, live-attenuated, contains live, weakened virus with a limited ability to reproduce. Vaccines for measles, mumps, Rubella, chickenpox, and varicella are made in this way. In live-attenuated vaccines, because the virus does not reproduce effectively, disease does not occur due to the vaccine. However, vaccine viruses are able to replicate just enough to induce “memory B cells” in the body, which then protect against future infections. An advantage of using live, weakened viruses is that one or two doses typically provide life-long immunity. A disadvantage is that persons with weakened immune systems usually cannot receive this type of vaccine (CHOP, 2021).

Another type of vaccine, inactivated, contains virus that is completely inactivated (killed) using a chemical. This “dead” virus cannot reproduce. Examples of inactivated vaccines include polio, hepatitis A, influenza, and rabies. The inactivated virus is still recognized by the immune system, which protects against disease development. Benefits of this type of vaccine are that the vaccine cannot cause even a mild form of the disease, and these vaccines can be administered to people with weakened immune systems. A disadvantage is that it usually requires several doses to achieve immunity (CHOP, 2021).

Using a part of the virus to make the vaccine is another strategy. These are referred to as recombinant, polysaccharide, and conjugate vaccines. Examples include the vaccines for hepatitis B, shingles, and HPV. These vaccines can also be given to people whose immune systems are compromised (CHOP, 2021).

Several COVID-19 vaccines are made by providing the genetic code (DNA, mRNA, or vectored viruses) for part of the vaccine. The immune system recognizes that the genetic code is foreign to the body, and the immune system responds against it. Thus, the next time someone is exposed to the virus, the immune system is ready to provide a rapid response (CHOP, 2021).

COVID-19 Vaccines

Several vaccines have been approved for COVID-19 infection, and others continue to be developed. Information about these vaccines continues to change. (For the most current information about COVID-19 vaccines, see “Resources” at the end of this course.)

Pfizer-BioNTech: Research indicates that this mRNA vaccine is up to 95% effective at preventing symptomatic disease. Initially, this vaccine had to be shipped in ultra-cold, temperature-controlled units. Now, however, the stability of the vaccine is secured when stored at temperatures more commonly found in pharmaceutical refrigerators and freezers. This vaccine requires two injections, 21 days apart.
Moderna: Data show that this mRNA vaccine is about 86% effective in people ages 65 and older and 94.1% effective in younger persons. This vaccine requires two injections, 28 days apart.
Johnson & Johnson / Janssen: This viral vector vaccine was granted emergency use approval by the FDA in the United States. It requires only one injection. A warning label states that the vaccine is associated with an uncommon, but potentially serious, blood clotting disorder.
Oxford-AstraZeneca: This vaccine is distributed in the United Kingdom and other European countries and is not available in the United States. Its use was temporarily suspended in some countries due to a rare side effect of blood clots with low blood platelets. It requires two doses, four to 12 weeks apart.
Novavax: As of June 2020, this vaccine is being studied and is not in use. Preliminary data suggest that it is 96.4% effective in reducing mild and moderate disease and 100% against severe disease from the original strain of COVID-19.
(Yale Medicine, 2021)

Common Reasons for COVID-19 Vaccine Hesitancy

Despite the history of vaccines’ ability to stop disease, some people are hesitant to be immunized in this way. In the case of the COVID-19 vaccine, many reasons have been cited for such hesitancy:

Distrust of vaccines: Some people believe that vaccines do not work or that they will get sick from the vaccines. Others are concerned that, despite being disproven, there is a link between vaccines and autism disorder.
Vaccine timeline: Some people are hesitant to be vaccinated because they believe that the COVID-19 vaccine is too new and was created too quickly.
Effectiveness: People want answers to questions about the effectiveness of the vaccine. Since both COVID-19 and its vaccines are new, some of these questions simply cannot be answered yet. Early studies, however, show that the vaccines are generally safe and effective.
Side effects: Some people fear possible side effects or long-term complications of receiving a vaccine.
Lower concern about the virus: Some people and groups do not believe that they are at risk of serious disease from the COVID virus. Or they may believe that the risks of the vaccine outweigh the risks of having the disease.
Government trust: Research indicates that vaccine acceptance depends on how much people trust their government. For example, in Asian countries where most citizens trust the government, acceptance of the vaccine is nearly 80%. In the United States, acceptance is estimated to be 69%. In countries with low government trust, such as Russia, the acceptance rate is less than 50%.
(CHOP, 2021)

Part of the vaccine process is addressing the issue of vaccine hesitancy. Experts note that addressing concerns about side effects, safety, registration, and access are critical to the success of any vaccine program.

Suggestions for increasing vaccine compliance and reducing vaccine hesitancy include building trust by having in-person conversations with community leaders such as religious leaders, local elected officials, etc. If community leaders support vaccine use, members of the public are more likely to support it as well (Firth, 2021).

It is also important to improve access to the vaccine, which is another barrier to increasing vaccination rates. Proposals to increase access include:

Creating a centralized database to help identify at-risk persons
Simplifying vaccine registration by increasing telephone registration and outreach programs
Expanding mobile vaccination to target the areas where access is limited
Establishing programs to administer the vaccine to people who are homebound
(Firth, 2021)