Moderna COVID-19 vaccine
The Moderna COVID19 vaccine, sold under the brand name Spikevax among others, is a COVID-19 vaccine developed by the American company Moderna, the United States National Institute of Allergy and Infectious Diseases, and the Biomedical Advanced [Research and Development Authority]. Depending on the jurisdiction, it is authorized for use in humans aged six months, twelve years, or eighteen years and older. The Moderna COVID19 vaccine provides protection against COVID-19, which is caused by infection by the SARS-CoV-2 virus. In May 2025, a different version of the Moderna COVID-19 vaccine, with the brand name Mnexspike, was approved for medical use in the United States.
Spikevax is designed to be administered in two or three 0.5-mL doses given by intramuscular injection, primarily into the deltoid muscle, at an interval of at least 28 days apart. The World Health Organization advises an eight-week interval between doses to optimize efficacy. Additional booster doses are approved in some regions to maintain immunity. Clinical trials and real-world data have demonstrated the vaccine's high efficacy, with significant effectiveness observed two weeks post-administration of the second dose, offering 94% protection against Covid and robust defense against severe cases. The vaccine's efficacy spans various demographics, including age, sex, and those with high-risk medical conditions.
Spikevax is an mRNA vaccine composed of nucleoside-modified mRNA encoding a spike protein of SARS-CoV-2, which is encapsulated in lipid nanoparticle|lipid nanoparticles]. In August and September 2022, bivalent versions of the vaccine containing elasomeran/elasomeran 0-omicron were authorized for use as booster doses in individuals aged 18 or older in the United Kingdom, Switzerland, Australia, Canada, the European Union, and the United States. The second component of the version of the bivalent vaccine used in the United States is based on the Omicron BA.4/BA.5 variant, while the second component of the bivalent vaccine version used in other countries is based on the Omicron BA.1 variant. The vaccine's effectiveness against variants has been extensively studied, indicating varying degrees of protection. For instance, during the prevalence of the Delta variant, effectiveness against infection slightly decreased over time. The vaccine's longevity and continuous protection are under study, with ongoing research focusing on its duration of effectiveness, which remains partially undetermined as of the latest updates.
The safety profile of the vaccine is favorable, with common side effects including injection site pain, fatigue, and headaches. Severe reactions like anaphylaxis are exceedingly rare. Concerns regarding myocarditis, have been identified but are typically mild and manageable. The vaccine's formulation utilizes mRNA technology, encapsulated within lipid nanoparticles to ensure cellular uptake and immune system response.
Medical uses
The Moderna COVID19 vaccine is used to provide protection against infection by the SARSCoV2 virus in order to prevent COVID19.The vaccine is given by intramuscular injection into the deltoid muscle of the arm. The initial course consists of two doses. The World Health Organization recommends an interval of eight weeks between doses.
A third, fourth, or fifth dose can be added in some countries.
Efficacy
Evidence of vaccine efficacy starts about two weeks after the first dose. High efficacy is achieved with full immunization, two weeks after the second dose, and was evaluated at 94.1%: at the end of the vaccine study that led to emergency authorization in the US, there were eleven cases of COVID19 in the vaccine group versus 185 cases in the placebo group. Moreover, there were zero cases of severe COVID19 in the vaccine group, versus eleven in the placebo group. This efficacy has been described as "astonishing" and "borderline historic" for a respiratory virus vaccine, and it is similar to the efficacy of the Pfizer–BioNTech [COVID-19 vaccine].Efficacy estimates were similar across age groups, sexes, racial and ethnic groups, and participants with medical comorbidities associated with high risk of severe COVID19. Only individuals aged 18 or older were studied. Studies are underway to gauge efficacy and safety in children aged 0–11 and 12–17.
A further study conducted by the US Centers for Disease Control and Prevention between December 2020, and March 2021, on nearly 4thousand health care personnel, first responders, and other essential and frontline workers concluded that under real-world conditions, mRNA vaccine effectiveness of full immunization was 90% against SARS-CoV-2 infections, regardless of symptoms, and vaccine effectiveness of partial immunization was 80%.
The duration of protection provided by the vaccine is unknown as of 2021, and a two-year followup study is underway to determine the duration.
Preliminary results from a phase III trial indicate that vaccine efficacy is durable, remaining at 93% six months after the second dose.
Effectiveness
A vaccine is generally considered effective if the estimate is ≥50% with a >30% lower limit of the 95% confidence interval. Effectiveness is generally expected to slowly decrease over time.In August 2021, results from a study suggested that the effectiveness against infection decreased from to when the Delta variant became predominant in the US, which may be due to unmeasured and residual confounding related to a decline in vaccine effectiveness over time.
Specific populations
Limited data are available on the safety of the Moderna COVID19 vaccine during pregnancy. The initial study excluded pregnant women or discontinued them from vaccination upon a positive pregnancy test. Studies in animals found no safety concerns and clinical trials are underway to evaluate the safety and efficacy of COVID19 vaccines in pregnant women. Real-world observations through the CDC v-safe tracking program have not uncovered unusual numbers of adverse events or outcomes of interest. Based on the results of a preliminary study, the US CDC recommends that pregnant women get vaccinated with the COVID19 vaccine.Adverse effects
The World Health Organization stated that "the safety data supported a favorable safety profile" and that the vaccine's AE profile "did not suggest any specific safety concerns". The most common adverse events were pain at the injection site, fatigue, headache, myalgia, and arthralgia.The US Centers for Disease Control and Prevention has reported anaphylaxis in 2.5 cases per million doses administered and has recommended a 15-minute observation period after injection. Delayed cutaneous reactions at injection sites resulting in rash-like erythemas have also been observed in rare cases but are not considered serious or contraindications to subsequent vaccination. The incidence rate for local adverse erythema is about 10.8%. In 1.9% of cases, redness may extend to a size of 100mm or greater.
In June 2021, the US CDC confirmed that myocarditis or pericarditis occurs in about 13 of every 1 million young people, mostly male and over the age of 16, who received the Moderna or the Pfizer–BioNTech vaccine. Most affected individuals recover quickly with adequate treatment and rest.
Additional side effects include extensive swelling of the vaccinated limb.
Pharmacology
Moderna's technology uses a nucleoside-modified messenger RNA compound codenamed mRNA-1273. The mRNA-1273 drug delivery system uses a PEGylated lipid nanoparticle drug delivery system. Once the compound is inside a human cell, the mRNA links up with the cell's endoplasmic reticulum. The mRNA-1273 is encoded to trigger the cell into making a specific protein using the cell's normal manufacturing process. The vaccine encodes a version of the spike protein with a modification called 2P, in which the protein includes two stabilizing mutations in which the original amino acids are replaced with prolines, developed by researchers at the University of Texas at Austin and the National Institute of Allergy and Infectious Diseases' Vaccine Research Center. Once the protein is expelled from the cell, it is eventually detected by the immune system, which begins generating efficacious antibodies.Chemistry
The vaccine contains the following ingredients:The active ingredient is an mRNA sequence containing a total of 4101 nucleotides that encodes the full-length SARS-CoV-2 spike glycoprotein, with two mutations designed to stabilize the pre-fusion conformation. The sequence is further optimized by:
- all uridines substituted with N1-methylpseudouridine,
- flanked by an artificial 5' untranslated region and a 3' UTR derived from the human alpha globin gene,
- introduction of two additional stop codons,
- terminated by a 3' poly tail.
The vaccine mRNA is dissolved in an aqueous buffer containing tromethamine, tromethamine hydrochloride, sodium acetate, and sucrose. The mRNA is encapsulated in lipid nanoparticles that stabilize the mRNA and facilitate its entry into cells. The nanoparticles are manufactured from the following lipids:
- 1,2-distearoyl-sn-glycero-3-phosphocholine,
- cholesterol,
- PEG2000-DMG 2000-dimyristoyl glycerol ), and
- SM-102
Manufacturing
Moderna is relying extensively on contract manufacturing organizations to scale up its vaccine manufacturing process. The first step of the process—synthesis of DNA plasmids —has been handled by a contractor called Aldevron based in Fargo, North Dakota. For the remainder of the process, Moderna contracted with Lonza Group to manufacture the vaccine at facilities in Portsmouth, New Hampshire in the United States, and in Visp in Switzerland, and purchased the necessary lipid excipients from CordenPharma. Besides CMOs, Moderna also manufactures the vaccine at its own production facility in Norwood, Massachusetts. Another manufacturing site for the vaccines for the market outside the U.S. is in Geleen in the Netherlands, produced by its manufacturing partner Lonza. Earlier, Lonza did produce the vaccine for the EU, U.K. and Canada at its site in Switzerland only, but had to cut projected deliveries to the U.K. and Canada earlier in 2021 due to production issues.For the tasks of filling and packaging vials, Moderna entered into contracts with Catalent in the United States and Laboratorios Farmacéuticos Rovi in Spain. In April 2021, Moderna expanded its agreement with Catalent to increase manufacturing output at the latter's plant in Bloomington, Indiana. The expansion will allow Catalent to manufacture up to 400 vials per minute and fill an additional 80million vials per year. Later that month, Moderna announced its plans to spend billions of dollars to boost production of its vaccines, potentially tripling the output in 2022, claiming as well that it would make no less than 800million doses in 2021. The increase in production is in part attributed to improvements made by the company in manufacturing methods.
The Moderna news followed preliminary results from the Pfizer-BioNTech vaccine candidate, BNT162b2, with Moderna demonstrating similar efficacy, but requiring storage at the temperature of a standard medical refrigerator of for up to thirty days or for up to four months, whereas the Pfizer-BioNTech candidate requires ultracold freezer storage between. Low-income countries usually have cold chain capacity for only standard refrigerator storage, not ultracold freezer storage. In February 2021, the restrictions on the Pfizer vaccine were relaxed when the US Food and Drug Administration updated the emergency use authorization to permit undiluted frozen vials of the vaccine to be transported and stored at between for up to two weeks before use. The Moderna vaccine should not be stored at a temperature below.
In November 2020, Nature reported that "While it's possible that differences in LNP formulations or mRNA secondary structures could account for the thermostability differences , many experts suspect both vaccine products will ultimately prove to have similar storage requirements and shelf lives under various temperature conditions."
History
In June 2025, the European Medicines Agency announced that they are making data from the marketing authorization applications for COVID19 mRNA vaccines Comirnaty and Spikevax publicly available.Original version
In January 2020, Moderna announced development of an RNA vaccine, codenamed mRNA-1273, to induce immunity to SARS-CoV-2.Moderna received from the Biomedical Advanced Research and Development Authority, an office of the US [Department of Health and Human Services]. BARDA funded 100% of the cost of bringing the vaccine to FDA licensure.
The United States government provided $2.5billion in total funding for the Moderna COVID19 vaccine. Private donors also made contributions to the vaccine's development. The Dolly Parton COVID-19 Research Fund contributed $1million.
Phase I–II clinical trials
In March 2020, the phaseI human trial of mRNA-1273 began in partnership with the US National Institute of Allergy and Infectious Diseases. In April, the US Biomedical Advanced Research and Development Authority allocated up to $483million for Moderna's vaccine development. Plans for a phaseII dosing and efficacy trial to begin in May were approved by the US Food and Drug Administration. Moderna signed a partnership with Swiss vaccine manufacturer Lonza Group, to supply 300million doses per annum.In May 2020, Moderna began a phaseIIa clinical trial recruiting six hundred adult participants to assess safety and differences in antibody response to two doses of its candidate vaccine, mRNA-1273, a study expected to complete in 2021.
In July 2020, Moderna scientists published preliminary results of the phaseI dose escalation clinical trial of mRNA-1273, showing dose-dependent induction of neutralizing antibodies against S1/S2 as early as 15 days post-injection. Mild to moderate adverse reactions, such as fever, fatigue, headache, muscle ache, and pain at the injection site were observed in all dose groups, but were common with increased dosage. The vaccine in low doses was deemed safe and effective in order to advance a phaseIII clinical trial using two 100-μg doses administered 29 days apart.
In September 2021, a study funded by the National Institute of Allergy and Infectious Diseases reported a strong immune response after six months, even at low doses, suggesting that more doses could be deployed from a limited vaccine supply. Six months after low-dose vaccination, 67% of participants still had memory cytotoxic T cells, suggesting that immune memory is stable. The study also found that cross-reactive T cells acquired during infection with other coronaviruses that cause the common cold increased the response to the vaccine.
Phase III clinical trials
Moderna and the National Institute of Allergy and Infectious Diseases began a phaseIII trial in the US in July 2020, with a plan to enroll and assign thirty-thousand volunteers to two groupsone group receiving two 100-μg doses of mRNA-1273 vaccine and the other receiving a placebo of 0.9% sodium chloride. As of 7August, more than 4,500 volunteers had enrolled.In September 2020, Moderna published the detailed study plan for the clinical trial. In September 2020, CEO Stéphane Bancel said that, if the trial is successful, the vaccine might be available to the public as early as late March or early April 2021. As of October 2020, Moderna had completed the enrollment of 30,000 participants needed for its phaseIII trial. The US National Institutes of Health announced in November 2020, that overall trial results were positive.
Since September 2020, Moderna has used Roche Diagnostics' Elecsys Anti-SARS-CoV-2 S test, authorized by the US Food and Drug Administration under an emergency use authorization in November 2020. According to an independent supplier of clinical assays in microbiology, "this will facilitate the quantitative measurement of SARS-CoV-2 antibodies and help to establish a correlation between vaccine-induced protection and levels of anti-receptor binding domain antibodies." The partnership was announced by Roche on 9December 2020.
A review by the FDA in December 2020, of interim results of the phaseIII clinical trial on mRNA-1273 showed it to be safe and effective against COVID19 infection resulting in the issuance of an EUA by the FDA.
In February 2021, results from phaseIII clinical trial were published in the New England Journal of Medicine, indicating 94% efficacy in preventing COVID19 infection. Side effects included flu-like symptoms, such as pain at the injection site, fatigue, muscle pain, and headache. The clinical trial is ongoing and is set to conclude in late 2022.
Pregnant and breastfeeding women were also excluded from the initial trials used to obtain the emergency use authorization, though trials in those populations were expected to be performed in 2021.
In March 2021, in order to increase the span of vaccination beyond adults, Moderna started the clinical trials of vaccines on children age 6-months to 11-years-old in the US and in Canada, in addition to the existing and fully-enrolled study on 12-17 year-olds.
Additional trials were completed—NCT04796896, NCT04649151, and NCT05436834.
Authorizations
Expedited
As of December 2020, the Moderna COVID19 vaccine was under evaluation for emergency authorization or approval by multiple countries which would enable rapid rollout of the vaccine in the United Kingdom, the European Union, Canada, and the United States.In December 2020, the Moderna COVID19 vaccine was authorized by the US Food and Drug Administration under an emergency use authorization for people aged 18 years of age and older. This is the first product from Moderna that has been authorized by the FDA. In June 2022, the EUA was expanded to include people aged six months through sixteen years of age. In April 2023, the authorization for the original, monovalent, version of the vaccine in the US was withdrawn. As of April 2023, only the bivalent version of the vaccine is authorized in the US.
In December 2020, the Moderna COVID19 vaccine was authorized by Health Canada.
In January 2021, the Moderna COVID19 vaccine was authorized for use in Israel by its Ministry of Health.
In February 2021, the Moderna COVID19 vaccine was authorized for use in Singapore by its Health Sciences Authority.
In April 2021, the World Health Organization granted emergency use listing.
In May 2021, the Moderna COVID19 vaccine was authorized for emergency use in the Philippines by the Philippines Food and Drug Administration.
In 2020, Moderna partnered with Takeda Pharmaceutical Company, and the Japan Ministry of Health, Labour and Welfare. The vaccine is known as "COVID-19 Vaccine Moderna Intramuscular Injection". In May 2021, COVID19 Vaccine Moderna Intramuscular Injection was authorized for emergency use in Japan.
In June 2021, the Moderna COVID19 vaccine was authorized for use in India by the Drugs Controller General of India. The same day, the vaccine was also approved by the Ministry of Health of Vietnam for emergency use in the country.
In August 2021, Malaysia's National Pharmaceutical Regulatory Agency gave conditional registration for emergency use of the Moderna COVID19 vaccine.
Standard
In January 2021, the Committee for Medicinal Products for Human Use of the European Medicines Agency recommended granting conditional marketing authorization and the recommendation was accepted by the European Commission the same day. In July 2021, the EMA extended the use of the COVID19 Vaccine Moderna to include people aged 12 to 17.In January 2021, Swissmedic granted temporary authorization for the Moderna COVID-19 mRNA Vaccine in Switzerland.
In March 2021, the Medicines and Healthcare products Regulatory Agency granted conditional marketing authorization in the United Kingdom.
In August 2021, Spikevax was granted provisional approval in Australia. The approval was updated in September 2021, to include people aged twelve and older.
The Moderna Spikevax COVID-19 vaccine was authorized in Canada in September 2021, for people aged 12 and older.
The Moderna Spikevax COVID-19 vaccine was authorized in the US in January 2022, for people aged 18 and older.
The Moderna Spikevax Bivalent Zero/Omicron vaccine was approved for medical use in the United Kingdom in August 2022.
In September 2022, the CHMP of the EMA recommended converting the conditional marketing authorizations of the vaccine into standard marketing authorizations. The recommendation covers all existing and upcoming adapted Spikevax vaccines, including the recently approved adapted Spikevax bivalent Original/Omicron BA.1.
In July 2025, Spikevax was fully approved in the US for use in children aged six months through eleven years of age who are at increased risk for COVID-19 disease.
In December 2025, the CHMP adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Mnexspike, intended for the prevention of COVID-19 in people from twelve years of age. The applicant for this medicinal product is Moderna Biotech, Spain, S.L.
Boosters
In January 2021, Moderna announced that it would offer a third dose of its vaccine to people who were vaccinated twice in its phaseI trial. The booster would be made available to participants six to twelve months after they got their second dose. The company said it may also study a third shot in participants from its phaseIII trial, if antibody persistence data warranted it. It also started testing to see if a third shot of the existing vaccine could be used to fend off the virus variants.In August 2021, the US Food and Drug Administration and the US [Centers for Disease Control and Prevention] authorized the use of an additional mRNA vaccine dose for immunocompromised individuals.
In September 2021, the Committee for Medicinal Products for Human Use of the European Medicines Agency started evaluating the use of a booster dose of the Moderna COVID-19 vaccine to be given at least six months after the second dose in people aged twelve years and older.
In October 2021, the European Medicines Agency stated that people with "severely weakened" immune systems can receive an extra dose of either the Pfizer–BioNTech COVID-19 vaccine or the Moderna COVID-19 vaccine starting at least 28 days after their second dose.
In October 2021, the US Food and Drug Administration and the Centers for Disease Control and Prevention authorized the use of either homologous or heterologous vaccine booster doses. The authorization was expanded to include all adults in November 2021.
Variants
In January 2021, Moderna started development of a new form of its vaccine, called mRNA-1273.351, that could be used as a booster shot against the Beta variant. In February 2021, Moderna announced that it had manufactured and shipped sufficient amounts of mRNA-1273.351 to the National Institutes of Health to run phaseI clinical trials. Moderna also investigated a multivalent booster, mRNA-1273.211, which combines a 50-50 mix of mRNA-1273 and mRNA-1273.351.A bivalent version of the vaccine containing elasomeran/imelasomeran was approved for use in the United Kingdom and in Australia in August 2022. It was approved for use in Canada in September 2022.
In October 2022, the FDA amended the authorization for the bivalent booster to cover people aged six years of age and older. In December 2022, the FDA amended the authorization for the bivalent booster to cover people aged six months and older.
XBB.1.5 monovalent vaccine
In September 2023, the FDA approved an updated a monovalent component Omicron variant XBB.1.5 version of the vaccine as a single dose for individuals aged twelve years of age and older; and authorized the Moderna COVID-19 Vaccine 2023-2024 formula under emergency use for individuals aged 6 months through 11 years of age. The updated version was tested in a small human trial of 101 participants; 50 received the monovalent XBB.1.5 version, compared to 51 who received a version containing XBB.1.5, BA.4 and BA.5. All participants had previously received four doses of older formulations of the Moderna COVID-19 vaccine. The safety profile of the authorized XBB.1.5 was found to be "consistent with previously authorized vaccines." The approvals and emergency authorizations for the bivalent version of the vaccine were revoked. Health Canada authorized the Moderna Spikevax COVID-19 vaccine in September 2023. The MHRA approved the use of the Moderna XBB.1.5 vaccine in September 2023.JN.1 monovalent vaccine
In September 2024, the UK's Medicines and Healthcare products Regulatory Agency approved Moderna's JN.1-adapted COVID-19 vaccine for use in adults and children aged six months and older.In September 2024, the European Union authorized the Spikevax JN.1 vaccine.
In September 2024, Swissmedic authorized the Spikevax JN.1 vaccine.
In September 2024, the Taiwan Food & Drug Administration authorized the Spikevax JN.1 vaccine.
KP.2 monovalent vaccine
In August 2024, the FDA approved and granted emergency authorization for a monovalent Omicron KP.2 version of the Moderna COVID-19 vaccine. The approval of Spikevax was granted to ModernaTX Inc. and the EUA amendment for the Moderna COVID-19 Vaccine was issued to ModernaTX Inc.Society and culture
About 155million doses of the Moderna COVID-19 vaccine, including about 3.1million doses in children and adolescents were administered in the EU/EEA from authorization to 26 June 2022.Brand names
mRNA-1273 was the code name during development and testing, elasomeran is the international nonproprietary name, and Spikevax is the brand name.Davesomeran is the INN for the BA.5 variant in the bivalent version of the vaccine. Andusomeran is the INN for the XBB 1.5 variant version of the vaccine.
Economics
In June 2020, Singapore signed a pre-purchase agreement for Moderna, reportedly paying a price premium in order to secure early stock of vaccines, although the government declined to provide the actual price and quantity, citing commercial sensitivities and confidentiality clauses.In August 2020, the US government signed an agreement to buy 100million doses of Moderna's anticipated vaccine, which the Financial Times said Moderna planned to price at per course. In November 2020, Moderna said it will charge governments who purchase its vaccine between and per dose while the EU is seeking a price of under per dose for the 160million doses it plans to purchase from Moderna.
In 2020, Moderna obtained purchase agreements for mRNA-1273 with the European Union for 160million doses and with Canada for up to 56million doses. In December 2020, a tweet by the Belgium Budget State Secretary revealed the E.U. would pay per dose, while The New York Times reported that the US would pay per dose.
Moderna reported revenue of from its COVID19 vaccine in 2020, and $17.7billion in 2021.
Paused vaccinations
Out of concern that the vaccine may increase the risk of myocarditis in young people under age 30, Finland, Sweden, Germany, and France recommended Moderna vaccinations not be used for this age group in October/November 2021.Controversies
In May 2020, after releasing partial and non-peer-reviewed results for only eight of 45 candidates in a preliminary pre-phaseI stage human trial directly to financial markets, the CEO announced on CNBC an immediate $1.25billion rights issue to raise funds for the company, at a $30billion valuation, while Stat said, "Vaccine experts say Moderna didn't produce data critical to assessing COVID19 vaccine."In July 2020, disputes between Moderna and government scientists over the company's unwillingness to share data from the clinical trials were revealed.
Moderna also faced criticism for failing to recruit people of color in clinical trials.
In August 2021, the US Department of Health and Human Services announced a plan to offer a booster dose eight months after the second dose, citing evidence of reduced protection against mild and moderate disease and the possibility of reduced protection against severe disease, hospitalization, and death. Scientists and the WHO reaffirmed the lack of evidence on the need for a booster dose for healthy people and that the vaccine remains effective against severe disease months after administration. In a statement, the WHO and SAGE said that, while protection against infection may be diminished, protection against severe disease will likely be retained due to cell-mediated immunity. Research into optimal timing for boosters is still ongoing, and a booster too early may lead to less robust protection.
Misinformation
Videos on video-sharing platforms circulated around May 2021 showing people having magnets stick to their arms after receiving the vaccine, purportedly demonstrating the conspiracy theory that vaccines contain microchips, but these videos have been debunked.In November 2021, a White House correspondent for the conservative outlet Newsmax falsely tweeted that the Moderna vaccine contained luciferase "so that you can be tracked."