First Safety Data Reports from CDC's V-Safe Tracking System: Comparing Moderna and Pfizer;  and Janssen One-Dose with Pfizer Dose Two

March 11, 2021 (updated May 5, 2021)

- The CDC released its first vaccine safety report (in the MMWR publication) on February 26 providing highlights  received through its "V-Safe" Covid-19 vaccine tracking system as well as through the VAERS (Vaccine Adverse Event Reporting System). VAERS received 6,994 reports of COVID-19–associated adverse events during the period December 14, 2020  - January 13, 2021, with more than 90% of the non-long-term care facility reports classified as nonserious.

 About 1.5 million people submitted first-dose information and 235,000 people had submitted second-dose information to V-Safe as of January 13, 2021. The top side effect, experienced by over 70% of respondents, was soreness at injection site, followed by fatigue, which was experienced by about 30% of respondents. Second dose symptoms tended to be more severe than first dose, but did not last more than a day or two.

Comparing the side effects of the two vaccines, more people had reactions the day after getting Moderna vs. the the day after getting Pfizer. For both, reactions greatly subsided within 7 days.
Comparing Vaccine Reactions for Pfizer and Moderna CDC data

Data Source: MMWR February 26, 2021

While data has not been released yet for Dose 2 of the Moderna vaccine, we do have data to compare the first with the second dose of the Pfizer vaccine,
CDC vsafe data show that more people experience reactions after the second dose, particularly on the day after receiving the second dose ("Day 1" as defined by the CDC):
Comparing Vaccine Reactions for Pfizer=BioNTech Dose 1 vs. Dose 2 CDC Data


- Not appearing in the first CDC safety report is a strange but not serious side effect experienced by a small number of Moderna vaccine recipients after the first dose. A strong round red rash suddenly appears on the arm about a week after the vaccine is received. Called "covid vaccine arm," the rash goes away eventually and does not usually appear again after the second dose. A physician describes her 8th day delayed injection reaction in this Psychology Today article.
(Also read Ask a Patient Moderna experiences, which include some covid vaccine arm reactions.)

- On April 30, the CDC released its first safety report on the Janssen vaccine, based on V-safe and VAERS data. The chart below compares Dose 2 reactions for Pfizer with the One-dose Janssen reactions using V-safe data. Note that the percentage of people experiencing various types of reactions the day after receiving the shot is similar, although injection site pain is more frequently reported the day after receiving Dose 2 of the Pfizer vaccine:

Comparing Vaccine Reactions for Pfizer and Janssen CDC data

Status of recent vaccines approved internationally or in late stages of development

- February 27, the U.S. FDA gave emergency authorization for Janssen Biotech's COVID-19 vaccine, the third to be authorized in the U.S. The vaccine is single-dose, and works by using a "human adenoviral vector virus", which contains a gene from SARS-CoV-2. Cells make coronavirus spike proteins in response to that engineered virus, which triggers an immune response. The Janssen vaccine was paused during April 12–23, 2021 due to rare CVST events, which involve blood clots in the brain’s veins (not in the arteries, as is the case for most strokes).

 - While adenoviral vectors have been tested in far more people than mRNA vaccines, the technology is used in only one commercial vaccine today: a rabies vaccine used to immunize wild animals.

 - In third-stage clinical trials for the Janssen vaccine, the level of protection for moderate and severe COVID-19 disease varied by geographic area: 72% protection in the United States; 66% in Latin American countries; and 57% in South Africa, 28 days post-vaccination. The vaccine was 85% effective in preventing severe/critical cases of COVID-19 across all geographical regions. No COVID-related deaths occured in the vaccine group. The most commonly reported side effects were pain at the injection site, headache, fatigue, muscle aches and nausea; most were mild to moderate in severity and lasted 1-2 days.

- Novavax received Fast Track Designation from the FDA for its two-dose vaccine, which is in Phase 3 trials. Novavax was awarded a $60 million US Department of Defense contract towards its manufacture, and another $1.6 billion from Operation Warp Speed if the candidate is effective in clinical trials.

- Merck/IAVI and Merck/Themis vaccines are under development with OWS funding.

- Sanofi and GlaxoSmithKline have a vaccine in development with OWS funding.

- Oxford University/AstraZeneca's two-shot vaccine has been authorized for use by a growing number of countries. The U.S. has pre-purchased 300 million doses of the vaccine for $1.2 billion under Operation Warp Speed. The funds also helped pay for clinical trials research and clinical testing.While the vaccine has been shown to be effective against the U.K. virus variant, it has much less efficacy against the South African variant of the virus.  Johnson & Johnson and Novavax Inc. vaccines have also been found to be less effective against the South African variant.

  The Lancet international medical journal published the peer-reviewed clinical trials results for Russia’s Sputnik V vaccine, with data indicating that it is almost 92% effective in fighting COVID-19. It has already been approved for use in many countries (check the vaccine tracker kkfor a list).

RAPS vaccine tracker:

For more details on each of the vaccines on this page, along with other vaccines approved or in development worldwide, along with dates approved, use the The Regulatory Affairs Professional Society (RAPS) Covid-19 Vaccine Tracker. It includes vaccines under development around the world, along with what phase they are in, sponsor, and source of funding. Click the green plus symbol on the right column to view study design and more detail about each vaccine.

Also Check: Bloomberg Vaccine Tracker Timeline
The site provides data on vaccines given globally and in the U.S., and this page (scroll down the page to section called "Vaccine Timeline" ) provides a timeline of vaccines in development and distribution, including color-coded trial status, number of people in trials, effectiveness, and other data in easy to read chart.

 Have you gotten your Covid-19 vaccine? Because of the considerable lag time between when CDC V-Safe data is received and when it is shared with the public, please consider also sharing your experience at our web site. The ratings are available on the website within 24 hours of posting.

Click to read comments about or add your rating for the Moderna or Pfizer or Janssen vaccines.

These highlights are from recent Ask a Patient health newsletters. Subscribe on our home page.