Second dose of the Moderna vaccine, the expert: “Side effects may be more acute but not always”

Second dose of the Moderna vaccine, the expert: “Side effects may be more acute but not always”
Second dose of the Moderna vaccine, the expert: “Side effects may be more acute but not always”

The Modern vaccine it is among the first to have been administered in Italy for the fight against Covid. It is a mRNA (messenger RNA) vaccine against COVID-19 (modified at the nucleoside level). Two injections are planned for immunization, usually into the upper arm muscle, spaced apart at least 28 days from each other.

For the first dose, the most frequently observed side effects in the pivotal study were generally mild or moderate in severity and resolved within days of vaccination. The most common were pain and swelling at the injection site, fatigue, chills, fever, swelling or tenderness of the lymph nodes in the armpits, headache, pain in the muscles and joints, nausea and vomiting. These side effects have been seen in more than 1 in 10 people. And what happens after the second dose? Il Riformista asked Professor Annalisa Capuano, Clinical Pharmacologist at AOU “Luigi Vanvitelli” in Naples, Full Professor (University of Campania “L. Vanvitelli”) and head of the Campania Region Pharmacovigilance Center.

What are the side effects of the second dose of the Moderna vaccine?

Adverse reactions observed during experimental studies were generally mild or moderate in severity and resolved within days of vaccination. These included injection site pain, fatigue, headache, myalgia, arthralgia, chills, nausea, vomiting, fever, injection site swelling and redness. Pain in limb, enlarged lymph nodes, insomnia and feeling sick were uncommon, affecting less than 1 in 100 people, while acute peripheral facial paralysis occurred rarely in less than 1 in 1,000 people.

Why are the side effects more acute than those of the first dose of Moderna?

The explanation lies in the fact that after the first dose the innate immune system is activated immediately and the B and T cells which are the main actors of our immune system are already ready to “fight”. When the second dose is injected, the so-called adaptive or specific immunity comes into play which acts in a targeted way on the new coronavirus. B and T lymphocytes recall specific antibodies and in turn trigger a release of a substance with proinflammatory activity, cytokines. It is at this point that the adverse events described above can arise.

Can everyone have the same symptoms after the Moderna vaccine?

Absolutely not. Not everyone experiences adverse events after administration of the COVID-19 vaccine because the immune response to the vaccine is subject to strong inter-individual variability.

Are there particular categories that are more likely to have side effects after the second dose of Moderna?

The safety profile of this vaccine was evaluated in a Phase 3 clinical study conducted in the United States of 30,351 participants 18 years of age and older who received at least one dose of COVID-19 Modern Vaccine (n = 15,185) or placebo (inert substance) (n = 15,166). From the review of the data no particular differences emerged in terms of gender and age group although the incidence of some transient and non-serious adverse reactions was slightly higher in the younger age groups; specifically, events such as fatigue, headache, myalgia, arthralgia, chills, nausea, vomiting and fever occurred more in adults aged 18 to 65 years than in those aged ≥65 years.

Does the risk of thrombosis increase after the second dose of the Moderna vaccine?

There has been a lot of talk in Europe about the incidence of thrombosis for viral vector vaccines. To date, with regard to the vaccine in question (mRNA vaccine), the EMA’s Risk Assessment Committee (PRAC) has not highlighted any warning signs regarding the risk of thrombosis following its administration.

What symptoms should I look out for after the second dose of Moderna and if they appear what to do?

As reported by the Italian Medicines Agency, you should see your doctor immediately if you experience any of the following symptoms within 3 weeks of the injection: shortness of breath, chest pain, leg swelling, leg pain, abdominal pain (sore belly) and persistent neurological symptoms, such as severe and persistent headache, blurred vision, confusion or seizures, unusual skin bruising or petechiae found outside the injection site.

How many days after the second dose of the Moderna vaccine are you completely immune?

From the results of the studies conducted it emerged that COVID-19 Vaccine Moderna has an efficacy of 93.6% after 14 days from the second dose.

What does it mean that the vaccine is active? Will I no longer take Covid?

Active immunity occurs when the immune system is activated to make antibodies to fight a disease. It can be obtained by natural infection or following a vaccination. To date, scientific evidence suggests that a vaccinated person is at lower risk of progressing to a severe form of the disease, however it is still unclear whether COVID-19 vaccines also prevent infection and transmission. Research into active immunity following vaccination is ongoing, and there is still a lot to learn.

How long does the protection last after the second dose?

The term of protection is not yet defined with certainty because so far the observation period has been a few months. Knowledge about the other types of coronaviruses suggests it should be at least 9-12 months old.

Could there be a third dose of the Moderna vaccine as well?

To this day, the topic remains controversial. The studies were conducted evaluating only the administration of 2 doses and large-scale use is confirming high protection. It is not known, however, whether the immune response will decline over time and whether a third dose will be needed to maintain this protection. Furthermore, it is not known whether new variants of the virus will be able to circumvent the immune response generated by current vaccines. Great Britain has announced the start of a large-scale trial to evaluate the effectiveness of a third dose also against emerging variants. Probably, as with other vaccines, a booster dose will need to be given to ensure protection against the virus.

Will the third dose be the same as the previous ones or modified (perhaps depending on the variants)?

To date, there is no evidence that the variants cause more serious disease or make the vaccines currently used less effective, but COVID-19 vaccines may need to be modified to improve their effectiveness against the new variants.

Who will need to take the third dose? Will it be for all the vaccinated?

There is currently no scientific evidence indicating that a third dose should also be administered. It will be necessary to await further evidence to confirm this hypothesis.

What is the value of this antibody test and how should it be interpreted?

It should be noted that the serological test detects the presence of antibodies to the SARS-CoV-2 virus regardless of the class to which they belong, that is, regardless of whether they are IgM, IgG and IgA. On the contrary, the antibody test is an “instant” test but, unlike the normal serological test, it has a greater specificity towards the search for COVID-19 neutralizing antibodies. However, it should be remembered that the absence of specific antibodies does not necessarily mean the absence of immune memory. The reactivation capacity of B cells and T lymphocytes represents a very important resource, even if it is subject to individual variability.

Is it useful to get tested for antibodies?

The test can be useful for the quantitative determination of post-vaccination IgG antibodies and therefore to evaluate and monitor the efficacy of the vaccine over time. However, some recent studies have shown that although the persistence of antibodies decreases over months, the immunological memory of memory B cells (specific for the SARS-CoV-2 spike protein) and T lymphocytes lasts longer. long in time, up to at least 8 months after infection and probably for several years as already found after the SARS epidemic. It should be remembered that the amount of antibodies present in the blood after infection or after any vaccination is not indicative of greater or lesser protection.

Is the antibody test useful in deciding whether or not to take the second dose of vaccine?

There is currently no recommendation to perform antibody testing after the first dose in order to assess the feasibility or otherwise of the second dose. Only people who have experienced a severe allergic or non-allergic adverse reaction that resulted in hospitalization or a need for prolonged treatment, or were life-threatening on the first administration of one of the available COVID-19 vaccines not they must receive the second dose.

After the second dose of the vaccine, can you remove the mask and let your guard down?

Absolutely not. To date it is not yet clear, but studies are underway on whether the vaccine protects only from the severe form of the disease or if it is also effective in preventing the acquisition of the infection and / or its transmission to other people. Therefore, even those who are vaccinated must not let their guard down but must continue to observe all prevention measures.

Professional journalist and videomaker, in 2006 he started writing for various national and local newspapers dealing with news, culture and technology. He attended the Suor Orsola Benincasa School of Journalism in Naples. Among the various publications with which Roma has collaborated, the AdnKronos news agency,, the OmniNapoli news agency, Canale 21 and Il Mattino di Napoli. Proudly Neapolitan, she mostly deals with video and videoreportage. She is the author of the documentary “Lo Sfizzicariello – stories of redemption from mental distress”, special mention at the Naples Film Festival.

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