Dear Getu!
As far as I know, vaccines against COVID-19 under development require two doses of immunization
https://www.webmd.com/vaccines/covid-19-vaccine/news/20201216/covid-19-vaccines-101-faq
How many doses do you need?
Two doses are needed for each of the three “frontrunner” vaccines from Moderna, AstraZeneca, and Pfizer.
Based on their Phase 3 data the RNA vaccines offer abut 50% protection after one dose and 94-95% protection after the second.
No! Please see the link below.
https://www.telegraph.co.uk/global-health/0/covid-19-vaccine-oxford-moderna-astrazeneca-pfizer-coronavirus-uk-news/
Ellen: "...94-95% protection after the second dose..." : the reported protection includes only data from up to 7 days after booster. According to data from other viruses the numbers may go down to 5-10 % after several months.
Dear Getu Habte, two doses are required for the development of immunity.
https://www.sps.nhs.uk/articles/dosing-schedule-information-for-pfizer-biontech-covid-19-vaccine/
According to the type of vaccine used; eg with those of Pfizer and Moderna, NO!
Kindly check the following link:
https://www.bbc.com/future/article/20210114-covid-19-how-effective-is-a-single-vaccine-dose
Dear Getu Habte as already mentioned by Arvind Singh all currently approved COVID-19 vaccines require two shots. Please see e.g. this useful link entitled
"The first COVID-19 vaccines will likely require two shots"
https://www.theverge.com/2020/11/20/21587664/pfizer-moderna-covid-19-coronavirus-vaccine-two-doses-shots
Dear Getu Habte the situation could of course change fundamentally when oral COVID-19 vaccines become available in the future. I'm pretty sure that oral vaccines against COVID-19 will come in the not so distant future. In this context please also see this interesting link entitled
"Oral COVID-19 vaccine beckons, as ImmunityBio licenses iosBio tech"
https://pharmaphorum.com/news/oral-covid-19-vaccine-beckons-as-immunitybio-licenses-iosbio-tech/
P.S. When you are interested in the development of oral COVID-19 vaccines, you can check out the following RG thread entitled "What are the possibilities for an oral COVID-19 vaccine?" initiated by Hermann Gruenwald:
https://www.researchgate.net/post/What_are_the_possibilities_for_an_oral_covid-19_vaccine
No matter the number of doses or the vaccine administration route: current Covid-19 vaccines show significant reduction in protection against mutated variants, which is the major problem and still unaddressed issue.
Dear Getu Habte and Hermann Gruenwald yes! Johnson&Johnson has just announced the development of a single-shot vaccine against COVID-19. Please see this very recent link entitled
"Johnson & Johnson Announces Single-Shot Janssen COVID-19 Vaccine Candidate Met Primary Endpoints in Interim Analysis of its Phase 3 ENSEMBLE Trial"
https://www.jnj.com/johnson-johnson-announces-single-shot-janssen-covid-19-vaccine-candidate-met-primary-endpoints-in-interim-analysis-of-its-phase-3-ensemble-trial
Dear Getu Habte and Hermann Gruenwald here is another interesting link about the new single-dose COVIF-19 vaccine:
"Johnson & Johnson asks FDA to approve world’s first single-dose Covid vaccine"
https://www.theguardian.com/world/2021/feb/04/johnson-johnson-covid-19-vaccine-single-dose-fda
According to this article "The United States has agreed to pay $1bn for 100m doses, which J&J said it expected to supply in the first half of the year. The United States also has the option of purchasing an additional 200m doses."
I don't think so. From the experts, we need about two jabs for full protection.
Dear Sabuj Das it's correct that both the Moderna and Pfizer vaccines require two shots. However, this could change with the arrival of the J&J vaccine. Please see this very instructive article entitled
Comparing the Covid-19 vaccines developed by Pfizer, Moderna, and Johnson & Johnson
https://www.statnews.com/2021/02/02/comparing-the-covid-19-vaccines-developed-by-pfizer-moderna-and-johnson-johnson/
According to this article "Both the Moderna and the Pfizer vaccines require two shots: a priming dose, followed by a booster shot. The interval between Moderna doses is 28 days; for the Pfizer vaccine, it’s 21 days. The J&J vaccine is, as mentioned, a single-dose vaccine. The company is also testing a two-dose regimen, with the two shots given eight weeks apart. The results from that 30,000-person trial aren’t expected until sometime in May."
Getu Habte
People who have already had confirmed COVID-19 infection might only need a single dose of a mRNA vaccine.
https://www.bmj.com/content/372/bmj.n308
Thanks!
Dear Getu Habte this is certainly an important question. Thus far all approved vaccines against COVID-19 require two shots. However, only one jab will be sufficient in the case of the new Johnson & Johnson vaccine. In this context please see this very recent (published 2 days ago) article entitled
Johnson and Johnson vaccine: FDA finds the single-shot jab safe
https://www.bbc.com/news/world-us-canada-56186965
Please also see this very recent (published February 23, 2021) article entitled
Is One Vaccine Dose Enough After COVID-19 Infection?
https://directorsblog.nih.gov/2021/02/23/is-one-dose-of-covid-19-vaccine-enough-after-covid-19-infection/
J&J has been approved by the US FDA. Compared to other vaccines, J&J's is a low maintenance. It is one shot, and it does not require low-temperature storage.
Indeed: totally in agreement with what Mohialdeen Alotumi
says; but, likewise, Vadim S. Gorshkov is also right.